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Groups > sci.electronics.design > #742925 > unrolled thread
| Started by | "Don" <g@crcomp.net> |
|---|---|
| First post | 2026-04-12 05:34 +0000 |
| Last post | 2026-04-25 15:47 +1000 |
| Articles | 20 on this page of 102 — 10 participants |
Back to article view | Back to sci.electronics.design
CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-12 05:34 +0000
Re: CoB LED filament analysis JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-12 10:45 +0100
Re: CoB LED filament analysis JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-12 10:48 +0100
Re: CoB LED filament analysis JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-12 10:50 +0100
Re: CoB LED filament analysis JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-12 12:03 +0100
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-12 04:44 -0700
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-12 04:19 -0700
Re: CoB LED filament analysis piglet <erichpwagner@hotmail.com> - 2026-04-13 07:40 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-13 01:46 -0700
Re: CoB LED filament analysis piglet <erichpwagner@hotmail.com> - 2026-04-13 11:40 +0000
Re: CoB LED filament analysis JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-13 14:31 +0100
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-13 06:59 -0700
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-14 12:25 +0000
Re: CoB LED filament analysis JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-14 14:04 +0100
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-14 08:21 -0700
Re: CoB LED filament analysis Bill Sloman <bill.sloman@ieee.org> - 2026-04-15 02:48 +1000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-14 11:14 -0700
Re: CoB LED filament analysis piglet <erichpwagner@hotmail.com> - 2026-04-14 19:25 +0100
Re: CoB LED filament analysis JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-14 19:43 +0100
Re: CoB LED filament analysis piglet <erichpwagner@hotmail.com> - 2026-04-14 20:19 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-14 12:54 -0700
Re: CoB LED filament analysis JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-14 19:42 +0100
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-14 12:57 -0700
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-14 13:02 -0700
Re: CoB LED filament analysis piglet <erichpwagner@hotmail.com> - 2026-04-14 21:29 +0100
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-14 19:10 -0700
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-15 11:36 +0000
Re: CoB LED filament analysis piglet <erichpwagner@hotmail.com> - 2026-04-15 12:35 +0000
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-21 14:39 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-21 08:41 -0700
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-21 08:54 -0700
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-21 16:55 +0000
Re: CoB LED filament analysis Bill Sloman <bill.sloman@ieee.org> - 2026-04-22 03:54 +1000
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-21 21:05 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-21 17:03 -0700
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-21 12:26 -0700
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-22 01:44 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-21 19:16 -0700
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-24 13:37 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-24 07:55 -0700
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-24 08:04 -0700
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-24 16:43 +0000
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-24 20:15 +0000
Re: CoB LED filament analysis Bill Sloman <bill.sloman@ieee.org> - 2026-04-26 03:45 +1000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-25 11:14 -0700
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-25 22:56 +0000
Re: CoB LED filament analysis ehsjr <ehsjr@verizon.net> - 2026-04-25 21:33 -0400
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-26 02:18 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-25 20:08 -0700
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-26 04:44 +0000
Re: CoB LED filament analysis Arie de Muijnck <noreply@ademu.nl> - 2026-04-26 13:03 +0200
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-26 11:35 +0000
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-26 11:43 +0000
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-26 16:44 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-26 10:17 -0700
Re: CoB LED filament analysis Arie de Muijnck <noreply@ademu.nl> - 2026-04-26 19:58 +0200
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-26 19:22 +0000
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-05-19 03:30 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-05-19 08:26 -0700
Re: CoB LED filament analysis Arie de Muijnck <noreply@ademu.nl> - 2026-05-19 18:23 +0200
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-05-19 09:52 -0700
Re: CoB LED filament analysis Jeroen Belleman <jeroen@nospam.please> - 2026-04-26 20:30 +0200
Re: CoB LED filament analysis JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-26 18:24 +0100
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-26 17:52 +0000
Re: CoB LED filament analysis piglet <erichpwagner@hotmail.com> - 2026-04-26 19:17 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-25 20:10 -0700
Re: CoB LED filament analysis Jeroen Belleman <jeroen@nospam.please> - 2026-04-24 22:23 +0200
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-24 15:42 -0700
Re: CoB LED filament analysis Jeroen Belleman <jeroen@nospam.please> - 2026-04-25 10:53 +0200
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-26 12:05 -0700
Re: CoB LED filament analysis piglet <erichpwagner@hotmail.com> - 2026-04-26 19:20 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-27 12:49 -0700
Re: CoB LED filament analysis Bill Sloman <bill.sloman@ieee.org> - 2026-04-27 17:04 +1000
Re: CoB LED filament analysis Jeroen Belleman <jeroen@nospam.please> - 2026-04-27 10:59 +0200
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-27 08:11 -0700
Re: CoB LED filament analysis Bill Sloman <bill.sloman@ieee.org> - 2026-04-28 01:51 +1000
Re: CoB LED filament analysis Jeroen Belleman <jeroen@nospam.please> - 2026-04-27 21:40 +0200
Re: CoB LED filament analysis JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-22 16:36 +0100
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-22 17:10 +0000
Re: CoB LED filament analysis JM <sunaecoNoChoppedPork@gmail.com> - 2026-04-22 18:17 +0100
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-22 17:31 +0000
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-22 18:14 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-22 11:23 -0700
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-22 18:43 +0000
Re: CoB LED filament analysis Jeroen Belleman <jeroen@nospam.please> - 2026-04-22 23:50 +0200
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-22 11:24 -0700
Re: CoB LED filament analysis Bill Sloman <bill.sloman@ieee.org> - 2026-04-23 17:22 +1000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-23 07:58 -0700
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-23 17:15 +0000
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-23 21:26 +0000
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-24 02:53 +0000
Re: CoB LED filament analysis John R Walliker <jrwalliker@gmail.com> - 2026-04-24 18:19 +0100
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-24 10:39 -0700
Re: CoB LED filament analysis John R Walliker <jrwalliker@gmail.com> - 2026-04-24 21:39 +0100
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-24 15:19 -0700
Re: CoB LED filament analysis Bill Sloman <bill.sloman@ieee.org> - 2026-04-25 15:23 +1000
Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-24 17:45 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-24 11:12 -0700
Re: CoB LED filament analysis Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-04-24 18:30 +0000
Re: CoB LED filament analysis john larkin <jl@glen--canyon.com> - 2026-04-24 11:42 -0700
Re: CoB LED filament analysis Bill Sloman <bill.sloman@ieee.org> - 2026-04-25 15:49 +1000
Re: CoB LED filament analysis Bill Sloman <bill.sloman@ieee.org> - 2026-04-25 15:47 +1000
Page 4 of 6 — ← Prev page 1 2 3 [4] 5 6 Next page →
| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-05-19 09:52 -0700 |
| Message-ID | <105p0lp9i8ijn5hoa9guokdsul8ruhhepe@4ax.com> |
| In reply to | #744091 |
On Tue, 19 May 2026 18:23:33 +0200, Arie de Muijnck <noreply@ademu.nl> wrote: >On 2026-05-19 05:30, Don wrote: >> Don wrote: >>> Arie de Muijnck wrote: >>>> Don wrote: >>> >>> <snip> >>> >>>>> My attempts to appease audience obsession with a series shunt resistor >>>>> caused me to flip the scope's input impedance to "1M ohm AC" and >>>>> inadvertently leave it at that incorrect current probe setting. >>>>> After the scope's set to "1M ohm DC" a flat-line trace appears when >>>>> the two half-wave rectifiers are "off:" >>>>> >>>>> <https://crcomp.net/ledfilament/curveprobe4.png> >>>>> >>>>> If that's what Arie means by "required shunt load resistor," then the >>>>> original current probe curve also shows a more-or-less flat-line trace: >>>>> >>>>> <https://crcomp.net/ledfilament/curveprobe.png> >>>>> >>>>> And the anomaly again indicates capacitive current curve corruption >>>>> caused by the solderless breadboard. >>>> >>>> No, the phaseshift was caused by the current transformer being unloaded. >>>> The perfect load of a CT is a short (e.g. a transimpedance amplifier). >>>> The breadboard would not cause a measuremable shift. The scope probe alone is >>>> more capacitive. >> >> <snip> >> >>> In the end, I need to pay more attention to the response curves included >>> in Fluke's manual. If I remember correctly, in TROUBLESHOOTING ANALOG >>> CIRCUITS Bob Pease said he finds graphs more revealing than mathematical >>> analysis. >>> >>> It's time to end my participation in this thread. In closing, I hope >>> this Chinese aphorism is correctly displayed: >>> >>> ???????????????????? >>> >>> Not tempted by praise, not intimidated by criticism; walking >>> the path of principle, one remains upright and true to oneself. >> >> Now is the time to re-engage with this thread. >> >> A cheap CoB LED filament probably uses a Graetz bridge, constructed >> with aluminum wire bonding: >> >> COB technology is widely used in LED designs, providing >> higher lumen density and improved thermal management. >> Wire bonding enables compact LED arrays with efficient >> heat dissipation, leading to brighter, longer-lasting >> lighting solutions in automotive, industrial, and >> consumer applications. ... >> Wire bonding remains a crucial technology in modern >> electronics, offering flexibility and cost-efficiency in >> a variety of applications, including 3D ICs, power >> electronics, and COB LEDs. While material and >> manufacturing costs can vary, especially for high-volume >> production, the cost advantages of wire bonding become >> evident as production scales. [1] >> >> In regards to Arie's remarks, the Fluke i1000s is an AC current probe. >> In other words, a capacitor couples its current transformer to its >> transimpedance amplifier. Perhaps that capacitor is culpable? >> The Fluke i1000s 100 mV/A Users Manual [2] response curve shown in >> Figure 2 for a 100 mV/A range indicates a large phase shift is >> plausible. Yet all phase shift disappears when a CoB LED bulb is >> substituted for a bare metal filament. The breadboard's parasitic >> capacitance of 31 pF is negligible. >> >> EUREKA by USA Poet Laureate Edgar Allan Poe, argues that scientific >> inquiry begins with an intuitive leap of imagination and more-or-less >> ends with measurement. In other words, a hypothesis provides a roadmap >> to give direction to measurement. >> >> Here's the first image shared by me in this thread: >> >> <https://crcomp.net/ledfilament/curveprobe.png> >> >> It shows a color mismatch between the blue tinted voltage trace and the >> green tinged current curve. That's a crucial clue. >> My mind mulled this clue during a bicycle spin up a nearby mountain >> with Bach playing through the earbuds. Then an intuitive leap of >> imagination took place. >> What if neither the breadboard nor the probe's intrinsic parasitic >> capacitance causes the phase shift? Is it possible that an idling >> transformer mounted near the breadboard causes the anomaly? >> Yes, the idling transformer creates the problem. And a power switch >> added to the transformer to power it off when not in use restores the >> current curve to zero phase shift. >> >> Note. >> >> [1] <https://resources.altium.com/p/wire-bonding-modern-applications-technology-trends-and-cost-considerations> >> >> [2] <https://assets.fluke.com/manuals/i1000s__umeng0000.pdf> >> >> Danke, >> >> -- >> 73, Don, WD7Q veritas _|_ >> liberabit | >> https://www.qsl.net/wd7q vos | >> > > >I should have thought of that possibility. >As a youngster, I almost got a scope for free because it had an unstable trace with lots of hum. >"This must be a defective supply in an old scope, nobody wanted to repair." >When moving the scope to get at the backside cabling the trace changed a lot. >Pulling it away from the isolation transformer next to it cured the problem. >No free scope for me that time... > >Arie Old Eico-grade scopes had low voltage CRTs and usually no magnetic shielding, so were very sensitive to mag fields. A clamp-on split-core current transformer will have some sensitivity to local magnetic fields. He's trying to resolve milliamps using a 1000 amp CT! John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Jeroen Belleman <jeroen@nospam.please> |
|---|---|
| Date | 2026-04-26 20:30 +0200 |
| Message-ID | <10sllkl$1pmm5$1@dont-email.me> |
| In reply to | #743416 |
On 4/26/26 18:44, Don wrote: > See addendum 2 below. > > See addendum below. > > Arie de Muijnck wrote: >> Don wrote: >>> john larkin wrote: >>>> Don wrote: >>>>> john larkin wrote: >>>>>> Don wrote: >>>>>>> Don wrote: >>>>> >>>>> <snip> >>>>> >>>>>>> Game over. Lessons learned: >>>>>>> >>>>>>> 1. Pease hated solderless breadboards for a good reason: they introduce >>>>>>> stray capacitance. After the solderless breadboard is removed the >>>>>>> filament's current curve reverts to its true form with voltage and >>>>>>> current in phase. >>>>>> >>>>>> 10 pF maybe. A million times less than would explain what you are >>>>>> seeing. >>>>>> >>>>>> But yes, the plastic solderless things are awful. >>>>>> >>>>>> https://www.dropbox.com/scl/fi/pk2t79ipe26c62lw9xi82/Z412_Proto.JPG?rlkey= > jypa4wdmgqsvwu0l51rx1x445&raw=1 >>>>> >>>>> Bravo! If I remember correctly, you use a dental drill? My own freehand >>>>> dremel on copper isn't nearly as straight. Perhaps my new milling table >>>>> [1] will help. >>>> >>>> I use a Drenel with a carbide dental burr. >>>> >>>> >>>> >>>>> My media tends towards universal board. As an artiste associate, >>>>> appreciate my abstract art arrangement: >>>>> >>>>> <https://crcomp.net/ledfilament/circuit.png> >>>>> >>>>> Note how voltage and current perfectly align after the solderless >>>>> protoboard is swapped out and replaced by my abstract art arrangement: >>>>> >>>>> <https://crcomp.net/ledfilament/curveprobe3.png> >>>>> >>>> >>>> That still doesn't look right. What's the value of the series shunt >>>> resistor? >>> >>> OK, there's a fundamental misunderstanding. The green component on the >>> left hand side of my abstract art arrangement, entitled PROBE EMBRACES >>> LAMP, is a fuse. Because you can never be too careful with 1:1 isolation >>> transformer secondary Line voltages. >>> The big red clamp on the right side is a current probe. (One of my >>> goals is to learn how to use it.) Its P2 < P1 decal is oriented to point >>> from a higher isolated Line to a lower isolated Line. >>> And now that you mention it, the probe's current curve is relatively >>> fuzzy. Because it's being pushed to its limit. If I remember correctly, >>> a 100 ohm series shunt resistor paints a sharper trace. I'll drop the >>> probe and swap-in a series shunt soon and share its sharper current >>> curve. >> >> Do you mean you were using the current probe without its required shunt (not 'series shunt') load resistor? >> That would explain most of the problems, including phase shift etc. > > Yes, that's precisely what happened. At the very beginning, when this > topic was still embedded in another thread, I openly asked if anyone > knew how to use the i1000s Fluke current probe. Yet you're the first > person to offer any insight into its operation. > Fluke's own user guide is almost as useless as AI in this regard. > AI keeps circling around the same old set of websites using different > words to regurgitate its useless operating instructions with each > iteration. > > Perhaps now that the key phrase "required load resistor" is known, my > search results will return a useful operator guide. Thank you for your > insight. > > Addendum: > > And, by the way, there's yet another fundamental misunderstanding. In > place of a full wave rectifier, the CoB LED utilizes two half-wave > rectifiers, one at each end. Per piglet's xray interpretation, each > half-wave rectifier consists of two diodes. > > Addendum 2: > > My attempts to appease audience obsession with a series shunt resistor > caused me to flip the scope's input impedance to "1M ohm AC" and > inadvertently leave it at that incorrect current probe setting. > After the scope's set to "1M ohm DC" a flat-line trace appears when > the two half-wave rectifiers are "off:" > > <https://crcomp.net/ledfilament/curveprobe4.png> > > If that's what Arie means by "required shunt load resistor," then the > original current probe curve also shows a more-or-less flat-line trace: > > <https://crcomp.net/ledfilament/curveprobe.png> > > And the anomaly again indicates capacitive current curve corruption > caused by the solderless breadboard. > > In the end, AI did indeed mention the DC setting when using the probe. > > Danke, > > -- > 73, Don, WD7Q veritas _|_ > liberabit | > https://www.qsl.net/wd7q vos | > It still doesn't make sense. The Fluke current transformer has its shunt built in. There is no need to -indeed you should not- add another. It's designed to be loaded by 1MOhm//47pF. The manual for the probe is easy to find on line: <https://www.fluke.com/en-us/product/accessories/probes/fluke-i1000s>. ($811 for a transformer!! Preposterous! Who do they think they are?) Jeroen Belleman
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| From | JM <sunaecoNoChoppedPork@gmail.com> |
|---|---|
| Date | 2026-04-26 18:24 +0100 |
| Message-ID | <rgisuk1n8bm0r9mbv4iuq5hm33uslk9ns4@4ax.com> |
| In reply to | #743407 |
On Sun, 26 Apr 2026 11:43:21 -0000 (UTC), "Don" <g@crcomp.net> wrote: >And, by the way, there's yet another fundamental misunderstanding. In >place of a full wave rectifier, the CoB LED utilizes two half-wave >rectifiers, one at each end. Per piglet's xray interpretation, each >half-wave rectifier consists of two diodes. "And, by the way, there's yet another fundamental misunderstanding" There sure is.
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| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-04-26 17:52 +0000 |
| Message-ID | <20260426d@crcomp.net> |
| In reply to | #743421 |
JM wrote:
> Don wrote:
>
>>And, by the way, there's yet another fundamental misunderstanding. In
>>place of a full wave rectifier, the CoB LED utilizes two half-wave
>>rectifiers, one at each end. Per piglet's xray interpretation, each
>>half-wave rectifier consists of two diodes.
>
> "And, by the way, there's yet another fundamental misunderstanding"
>
> There sure is.
Yep.
Danke,
--
73, Don, WD7Q veritas _|_
liberabit |
https://www.qsl.net/wd7q vos |
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| From | piglet <erichpwagner@hotmail.com> |
|---|---|
| Date | 2026-04-26 19:17 +0000 |
| Message-ID | <10slobd$1qip2$1@dont-email.me> |
| In reply to | #743407 |
Don <g@crcomp.net> wrote: > See addendum below. > > Arie de Muijnck wrote: >> Don wrote: >>> john larkin wrote: >>>> Don wrote: >>>>> john larkin wrote: >>>>>> Don wrote: >>>>>>> Don wrote: >>>>> >>>>> <snip> >>>>> >>>>>>> Game over. Lessons learned: >>>>>>> >>>>>>> 1. Pease hated solderless breadboards for a good reason: they introduce >>>>>>> stray capacitance. After the solderless breadboard is removed the >>>>>>> filament's current curve reverts to its true form with voltage and >>>>>>> current in phase. >>>>>> >>>>>> 10 pF maybe. A million times less than would explain what you are >>>>>> seeing. >>>>>> >>>>>> But yes, the plastic solderless things are awful. >>>>>> >>>>>> https://www.dropbox.com/scl/fi/pk2t79ipe26c62lw9xi82/Z412_Proto.JPG?rlkey= > jypa4wdmgqsvwu0l51rx1x445&raw=1 >>>>> >>>>> Bravo! If I remember correctly, you use a dental drill? My own freehand >>>>> dremel on copper isn't nearly as straight. Perhaps my new milling table >>>>> [1] will help. >>>> >>>> I use a Drenel with a carbide dental burr. >>>> >>>> >>>> >>>>> My media tends towards universal board. As an artiste associate, >>>>> appreciate my abstract art arrangement: >>>>> >>>>> <https://crcomp.net/ledfilament/circuit.png> >>>>> >>>>> Note how voltage and current perfectly align after the solderless >>>>> protoboard is swapped out and replaced by my abstract art arrangement: >>>>> >>>>> <https://crcomp.net/ledfilament/curveprobe3.png> >>>>> >>>> >>>> That still doesn't look right. What's the value of the series shunt >>>> resistor? >>> >>> OK, there's a fundamental misunderstanding. The green component on the >>> left hand side of my abstract art arrangement, entitled PROBE EMBRACES >>> LAMP, is a fuse. Because you can never be too careful with 1:1 isolation >>> transformer secondary Line voltages. >>> The big red clamp on the right side is a current probe. (One of my >>> goals is to learn how to use it.) Its P2 < P1 decal is oriented to point >>> from a higher isolated Line to a lower isolated Line. >>> And now that you mention it, the probe's current curve is relatively >>> fuzzy. Because it's being pushed to its limit. If I remember correctly, >>> a 100 ohm series shunt resistor paints a sharper trace. I'll drop the >>> probe and swap-in a series shunt soon and share its sharper current >>> curve. >> >> Do you mean you were using the current probe without its required shunt >> (not 'series shunt') load resistor? >> That would explain most of the problems, including phase shift etc. > > Yes, that's precisely what happened. At the very beginning, when this > topic was still embedded in another thread, I openly asked if anyone > knew how to use the i1000s Fluke current probe. Yet you're the first > person to offer any insight into its operation. > Fluke's own user guide is almost as useless as AI in this regard. > AI keeps circling around the same old set of websites using different > words to regurgitate its useless operating instructions with each > iteration. > > Perhaps now that the key phrase "required load resistor" is known, my > search results will return a useful operator guide. Thank you for your > insight. > > And, by the way, there's yet another fundamental misunderstanding. In > place of a full wave rectifier, the CoB LED utilizes two half-wave > rectifiers, one at each end. Per piglet's xray interpretation, each > half-wave rectifier consists of two diodes. > > Danke, > > -- > 73, Don, WD7Q veritas _|_ > liberabit | > https://www.qsl.net/wd7q vos | > > What you call two half wave rectifiers are a full wave bridge, or if you prefer the inventors name a Graetz bridge. -- piglet
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-04-25 20:10 -0700 |
| Message-ID | <3g0rukpcap4ecilpsju92sj0042io4uv3d@4ax.com> |
| In reply to | #743381 |
On Sat, 25 Apr 2026 22:56:45 -0000 (UTC), "Don" <g@crcomp.net> wrote: >john larkin wrote: >> Don wrote: >>> Don wrote: > ><snip> > >>>Game over. Lessons learned: >>> >>> 1. Pease hated solderless breadboards for a good reason: they introduce >>> stray capacitance. After the solderless breadboard is removed the >>> filament's current curve reverts to its true form with voltage and >>> current in phase. >> >> 10 pF maybe. A million times less than would explain what you are >> seeing. >> >> But yes, the plastic solderless things are awful. >> >> https://www.dropbox.com/scl/fi/pk2t79ipe26c62lw9xi82/Z412_Proto.JPG?rlkey=jypa4wdmgqsvwu0l51rx1x445&raw=1 > >Bravo! If I remember correctly, you use a dental drill? My own freehand >dremel on copper isn't nearly as straight. Perhaps my new milling table >[1] will help. > My media tends towards universal board. As an artiste associate, >appreciate my abstract art arrangement: > > <https://crcomp.net/ledfilament/circuit.png> > >Note how voltage and current perfectly align after the solderless >protoboard is swapped out and replaced by my abstract art arrangement: > > <https://crcomp.net/ledfilament/curveprobe3.png> > >There's little, if any, wriggle room for the phase anomaly to caused by >anything other than stray capacitance from the solderless breadboard. > >Note. > >[1] <https://www.vevor.com/rotary-table-c_10128/compound-milling-machine-work-table-2-axis-cross-slide-bench-drill-vise-fixture-p_010230619047> > >Danke, One explanation is that the solderless breadboard wasn't connecting things. They tend to not do that. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Jeroen Belleman <jeroen@nospam.please> |
|---|---|
| Date | 2026-04-24 22:23 +0200 |
| Message-ID | <10sgjg4$bf5o$1@dont-email.me> |
| In reply to | #743312 |
On 4/24/26 18:43, Don wrote: > john larkin wrote: >> john larkin wrote: >>> Don wrote: >>>> john larkin wrote: >>>>> Don wrote: >>>>>> john larkin wrote: >>>>>>> john larkin wrote: >>>>>>>> Don wrote: >>>>>>>>> Don wrote: >>>>>>>>>> Recent thread topic transitioned to a tentative opinion on a work-in- >>>>>>>>>> progress webpage: >>>>>>>>>> >>>>>>>>>> <https://crcomp.net/ledfilament/index.php> >>>>>>>>>> >>>>>>>>>> Radiography imparts interesting insight. Second opinions welcome! >>>>>>>>>> The current waveform flopped. Any advice on how to use a Fluke >>>>>>>>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >>>>>>>>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on >>>>>>>>>> the current probe? >>>>>>>>> >>>>>>>>> Alright you guys, a couple of current curve images are now available on >>>>>>>>> the webpage. For the present case, in regards to the probe's "P2 < P1" >>>>>>>>> orientation decal, P1 designates Line while P2 indicates Neutral. >>>>>>>>> The probe provides a sharper, cleaner curve compared to the >>>>>>>>> resistor. Both curves illustrate how the silicon filament primarily >>>>>>>>> presents itself as a capacitive load. >>>>>>>>> The filament's high voltage combined with its low amperage degrades >>>>>>>>> resistor curve quality. It took a 10 M ohm resistive current sensor for >>>>>>>>> the half-wave rectification effect to become visible. >>>>>>>>> The probe curve's mostly blue trace shows the peak-to-peak Line >>>>>>>>> voltage. It's used to properly trigger the scope. (Perhaps the scope's >>>>>>>>> line trigger accomplishes the same result with less effort?) The probe >>>>>>>>> curve's mostly green trace shows the current, with peaks and valleys >>>>>>>>> created by half-wave rectification at each end of the filament. >>>>>>>>> The current curve is set to 2mV per division. Does anyone know how >>>>>>>>> to transpose it to mA? >>>>>>>> >>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>> >>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>> >>>>>>>> Unless one of the thingies on the end is a cap. A DC curve would >>>>>>>> resolve that. >>>>>>>> >>>>>>>> A thermal image would be interesting too. >>>>>>>> >>>>>>> No, it lights up with DC, so there's no series cap. >>>>>> >>>>>> ELI the ICE man. The trace of the current curve clearly leads the >>>>>> voltage trace, so the filament must present a capacitive load. >>>>>> A silicon device that presents a capactive load is different from >>>>>> a series capacitor: >>>>>> >>>>>> COB LEDs present capacitive loads through parasitic capacitances >>>>>> inherent to their densely packed chip-on-board structure. These >>>>>> capacitances arise between closely spaced LED dies, bonding >>>>>> wires, and the substrate, affecting driver circuits during >>>>>> switching. >>>>> >>>>> Since the current probe waveform is so different from the one that >>>>> uses a resistor, one must be wrong, or likely both. >>>>> >>>>> Stray capacitances are at least six orders of magnitude from causing >>>>> the phase shift that you are seeing. >>>> >>>> You're wrong, no doubt about it. Stray capacitance caused my problem. >>>> And your sweeping generality at this juncture led me to question my >>>> correct quantitative instincts. >>>> >>>> "ELI the ICE man. The trace of the current curve clearly leads the >>>> voltage trace" leads to the correct solution. >>>> >>>> Hint: stray capacitance originates from more than one source. >>> >>> Probably the biggest capacitance is the LEDs themselves. >> >> Or the rectifier diodes. But still not much c. >> >> Measure it. >>> >>> If you used a sensible value current shunt resistor - ohms and not >>> megohms - the effects of the capacitance would be invisible with 60 Hz >>> excitation. >>> >>> Measure the capacitance and do the math. Or Spice it. >>> >>> "ELI the ICE man" is not quantitative. > > OK, We'll do it your quantitative way. Stray capacitance is at least six > orders of magnitude higher than what you imagine. Because the biggest > capacitance does not originate with the filament. > > There's no need to goof with a shunt resistor when an accurate current > probe measurement is already available: > > <https://crcomp.net/ledfilament/curveprobe.png> > > It shows you everything you need to do your own math. Show me your > math and I'll included on my webpage, with your permission. > > Hint for people who still don't see the light (so to speak): Bob Pease > said, "My favorite programming language is solder." On a related note, > Pease passionately hated one piece in particular, amid the equipment > found in an electronic lab. > > Danke, > > -- > 73, Don, WD7Q veritas _|_ > liberabit | > https://www.qsl.net/wd7q vos | > This still doesn't make sense, but you piqued me enough to make me do my own measurement. I don't see any phase shift between voltage and current, although the power factor is certainly far from unity. You can see my results here: <https://cern.ch/jeroen/LEDstring>. Jeroen Belleman
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-04-24 15:42 -0700 |
| Message-ID | <4arnuklt5a6olqtb0h77fab934tg1nbov9@4ax.com> |
| In reply to | #743332 |
On Fri, 24 Apr 2026 22:23:32 +0200, Jeroen Belleman <jeroen@nospam.please> wrote: >On 4/24/26 18:43, Don wrote: >> john larkin wrote: >>> john larkin wrote: >>>> Don wrote: >>>>> john larkin wrote: >>>>>> Don wrote: >>>>>>> john larkin wrote: >>>>>>>> john larkin wrote: >>>>>>>>> Don wrote: >>>>>>>>>> Don wrote: >>>>>>>>>>> Recent thread topic transitioned to a tentative opinion on a work-in- >>>>>>>>>>> progress webpage: >>>>>>>>>>> >>>>>>>>>>> <https://crcomp.net/ledfilament/index.php> >>>>>>>>>>> >>>>>>>>>>> Radiography imparts interesting insight. Second opinions welcome! >>>>>>>>>>> The current waveform flopped. Any advice on how to use a Fluke >>>>>>>>>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >>>>>>>>>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on >>>>>>>>>>> the current probe? >>>>>>>>>> >>>>>>>>>> Alright you guys, a couple of current curve images are now available on >>>>>>>>>> the webpage. For the present case, in regards to the probe's "P2 < P1" >>>>>>>>>> orientation decal, P1 designates Line while P2 indicates Neutral. >>>>>>>>>> The probe provides a sharper, cleaner curve compared to the >>>>>>>>>> resistor. Both curves illustrate how the silicon filament primarily >>>>>>>>>> presents itself as a capacitive load. >>>>>>>>>> The filament's high voltage combined with its low amperage degrades >>>>>>>>>> resistor curve quality. It took a 10 M ohm resistive current sensor for >>>>>>>>>> the half-wave rectification effect to become visible. >>>>>>>>>> The probe curve's mostly blue trace shows the peak-to-peak Line >>>>>>>>>> voltage. It's used to properly trigger the scope. (Perhaps the scope's >>>>>>>>>> line trigger accomplishes the same result with less effort?) The probe >>>>>>>>>> curve's mostly green trace shows the current, with peaks and valleys >>>>>>>>>> created by half-wave rectification at each end of the filament. >>>>>>>>>> The current curve is set to 2mV per division. Does anyone know how >>>>>>>>>> to transpose it to mA? >>>>>>>>> >>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>> >>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>> >>>>>>>>> Unless one of the thingies on the end is a cap. A DC curve would >>>>>>>>> resolve that. >>>>>>>>> >>>>>>>>> A thermal image would be interesting too. >>>>>>>>> >>>>>>>> No, it lights up with DC, so there's no series cap. >>>>>>> >>>>>>> ELI the ICE man. The trace of the current curve clearly leads the >>>>>>> voltage trace, so the filament must present a capacitive load. >>>>>>> A silicon device that presents a capactive load is different from >>>>>>> a series capacitor: >>>>>>> >>>>>>> COB LEDs present capacitive loads through parasitic capacitances >>>>>>> inherent to their densely packed chip-on-board structure. These >>>>>>> capacitances arise between closely spaced LED dies, bonding >>>>>>> wires, and the substrate, affecting driver circuits during >>>>>>> switching. >>>>>> >>>>>> Since the current probe waveform is so different from the one that >>>>>> uses a resistor, one must be wrong, or likely both. >>>>>> >>>>>> Stray capacitances are at least six orders of magnitude from causing >>>>>> the phase shift that you are seeing. >>>>> >>>>> You're wrong, no doubt about it. Stray capacitance caused my problem. >>>>> And your sweeping generality at this juncture led me to question my >>>>> correct quantitative instincts. >>>>> >>>>> "ELI the ICE man. The trace of the current curve clearly leads the >>>>> voltage trace" leads to the correct solution. >>>>> >>>>> Hint: stray capacitance originates from more than one source. >>>> >>>> Probably the biggest capacitance is the LEDs themselves. >>> >>> Or the rectifier diodes. But still not much c. >>> >>> Measure it. >>>> >>>> If you used a sensible value current shunt resistor - ohms and not >>>> megohms - the effects of the capacitance would be invisible with 60 Hz >>>> excitation. >>>> >>>> Measure the capacitance and do the math. Or Spice it. >>>> >>>> "ELI the ICE man" is not quantitative. >> >> OK, We'll do it your quantitative way. Stray capacitance is at least six >> orders of magnitude higher than what you imagine. Because the biggest >> capacitance does not originate with the filament. >> >> There's no need to goof with a shunt resistor when an accurate current >> probe measurement is already available: >> >> <https://crcomp.net/ledfilament/curveprobe.png> >> >> It shows you everything you need to do your own math. Show me your >> math and I'll included on my webpage, with your permission. Iron-core current transformers get very nonlinear at low currents. The magnetic domains get sticky. You showed a gigantic CT. >> >> Hint for people who still don't see the light (so to speak): Bob Pease >> said, "My favorite programming language is solder." On a related note, >> Pease passionately hated one piece in particular, amid the equipment >> found in an electronic lab. >> >> Danke, >> >> -- >> 73, Don, WD7Q veritas _|_ >> liberabit | >> https://www.qsl.net/wd7q vos | >> > >This still doesn't make sense, but you piqued me enough to make >me do my own measurement. I don't see any phase shift between >voltage and current, although the power factor is certainly far >from unity. You can see my results here: ><https://cern.ch/jeroen/LEDstring>. > >Jeroen Belleman Was the curve on the left done at DC? Why is your voltage waveform flat-topped? At 100 volts? At 30 mA, your 1K resistor drops 30 volts. So the "Voltage" connector doesn't represent the voltage seen by the DUT. And does the "Voltage" connector go straight into a scope channel? No probe? Your current waveform does have about the right shape and timing. No time lags. The x-rayed COB seems to have a 4-diode bridge rectifier, two resistors, and one string of LEDs. That is more cost effective than having two strings, twice as many LEDs, each on half the time. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Jeroen Belleman <jeroen@nospam.please> |
|---|---|
| Date | 2026-04-25 10:53 +0200 |
| Message-ID | <10shves$mghu$1@dont-email.me> |
| In reply to | #743336 |
On 4/25/26 00:42, john larkin wrote: > On Fri, 24 Apr 2026 22:23:32 +0200, Jeroen Belleman > <jeroen@nospam.please> wrote: > >> On 4/24/26 18:43, Don wrote: >>> john larkin wrote: >>>> john larkin wrote: >>>>> Don wrote: >>>>>> john larkin wrote: >>>>>>> Don wrote: >>>>>>>> john larkin wrote: >>>>>>>>> john larkin wrote: >>>>>>>>>> Don wrote: >>>>>>>>>>> Don wrote: >>>>>>>>>>>> Recent thread topic transitioned to a tentative opinion on a work-in- >>>>>>>>>>>> progress webpage: >>>>>>>>>>>> >>>>>>>>>>>> <https://crcomp.net/ledfilament/index.php> >>>>>>>>>>>> >>>>>>>>>>>> Radiography imparts interesting insight. Second opinions welcome! >>>>>>>>>>>> The current waveform flopped. Any advice on how to use a Fluke >>>>>>>>>>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >>>>>>>>>>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on >>>>>>>>>>>> the current probe? >>>>>>>>>>> >>>>>>>>>>> Alright you guys, a couple of current curve images are now available on >>>>>>>>>>> the webpage. For the present case, in regards to the probe's "P2 < P1" >>>>>>>>>>> orientation decal, P1 designates Line while P2 indicates Neutral. >>>>>>>>>>> The probe provides a sharper, cleaner curve compared to the >>>>>>>>>>> resistor. Both curves illustrate how the silicon filament primarily >>>>>>>>>>> presents itself as a capacitive load. >>>>>>>>>>> The filament's high voltage combined with its low amperage degrades >>>>>>>>>>> resistor curve quality. It took a 10 M ohm resistive current sensor for >>>>>>>>>>> the half-wave rectification effect to become visible. >>>>>>>>>>> The probe curve's mostly blue trace shows the peak-to-peak Line >>>>>>>>>>> voltage. It's used to properly trigger the scope. (Perhaps the scope's >>>>>>>>>>> line trigger accomplishes the same result with less effort?) The probe >>>>>>>>>>> curve's mostly green trace shows the current, with peaks and valleys >>>>>>>>>>> created by half-wave rectification at each end of the filament. >>>>>>>>>>> The current curve is set to 2mV per division. Does anyone know how >>>>>>>>>>> to transpose it to mA? >>>>>>>>>> >>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>> >>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>> >>>>>>>>>> Unless one of the thingies on the end is a cap. A DC curve would >>>>>>>>>> resolve that. >>>>>>>>>> >>>>>>>>>> A thermal image would be interesting too. >>>>>>>>>> >>>>>>>>> No, it lights up with DC, so there's no series cap. >>>>>>>> >>>>>>>> ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>> voltage trace, so the filament must present a capacitive load. >>>>>>>> A silicon device that presents a capactive load is different from >>>>>>>> a series capacitor: >>>>>>>> >>>>>>>> COB LEDs present capacitive loads through parasitic capacitances >>>>>>>> inherent to their densely packed chip-on-board structure. These >>>>>>>> capacitances arise between closely spaced LED dies, bonding >>>>>>>> wires, and the substrate, affecting driver circuits during >>>>>>>> switching. >>>>>>> >>>>>>> Since the current probe waveform is so different from the one that >>>>>>> uses a resistor, one must be wrong, or likely both. >>>>>>> >>>>>>> Stray capacitances are at least six orders of magnitude from causing >>>>>>> the phase shift that you are seeing. >>>>>> >>>>>> You're wrong, no doubt about it. Stray capacitance caused my problem. >>>>>> And your sweeping generality at this juncture led me to question my >>>>>> correct quantitative instincts. >>>>>> >>>>>> "ELI the ICE man. The trace of the current curve clearly leads the >>>>>> voltage trace" leads to the correct solution. >>>>>> >>>>>> Hint: stray capacitance originates from more than one source. >>>>> >>>>> Probably the biggest capacitance is the LEDs themselves. >>>> >>>> Or the rectifier diodes. But still not much c. >>>> >>>> Measure it. >>>>> >>>>> If you used a sensible value current shunt resistor - ohms and not >>>>> megohms - the effects of the capacitance would be invisible with 60 Hz >>>>> excitation. >>>>> >>>>> Measure the capacitance and do the math. Or Spice it. >>>>> >>>>> "ELI the ICE man" is not quantitative. >>> >>> OK, We'll do it your quantitative way. Stray capacitance is at least six >>> orders of magnitude higher than what you imagine. Because the biggest >>> capacitance does not originate with the filament. >>> >>> There's no need to goof with a shunt resistor when an accurate current >>> probe measurement is already available: >>> >>> <https://crcomp.net/ledfilament/curveprobe.png> >>> >>> It shows you everything you need to do your own math. Show me your >>> math and I'll included on my webpage, with your permission. > > Iron-core current transformers get very nonlinear at low currents. The > magnetic domains get sticky. You showed a gigantic CT. > >>> >>> Hint for people who still don't see the light (so to speak): Bob Pease >>> said, "My favorite programming language is solder." On a related note, >>> Pease passionately hated one piece in particular, amid the equipment >>> found in an electronic lab. >>> >>> Danke, >>> >>> -- >>> 73, Don, WD7Q veritas _|_ >>> liberabit | >>> https://www.qsl.net/wd7q vos | >>> >> >> This still doesn't make sense, but you piqued me enough to make >> me do my own measurement. I don't see any phase shift between >> voltage and current, although the power factor is certainly far >>from unity. You can see my results here: >> <https://cern.ch/jeroen/LEDstring>. >> >> Jeroen Belleman > > > Was the curve on the left done at DC? No, it's the same data. I just plot I versus V. It's a bit noisy; I should have filtered it a bit. > Why is your voltage waveform flat-topped? At 100 volts? > > At 30 mA, your 1K resistor drops 30 volts. So the "Voltage" connector > doesn't represent the voltage seen by the DUT. True, the voltage recording is distorted by the superimposed current curve. That also explains the flat top. I could use a smaller current sense resistor, or compensate for its voltge drop. > > And does the "Voltage" connector go straight into a scope channel? No > probe? I used regular 1:10 scope probes. > Your current waveform does have about the right shape and timing. No > time lags. > > The x-rayed COB seems to have a 4-diode bridge rectifier, two > resistors, and one string of LEDs. That is more cost effective than > having two strings, twice as many LEDs, each on half the time. True. I expected my strings to be similar to Don's, but they weren't. > John Larkin > Highland Tech Glen Canyon Design Center > Lunatic Fringe Electronics Exposing in some detail what I did lends people the ability to really understand what's going on and to propose improvements. Don's measurements leave too much room for mystery. Jeroen Belleman
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-04-26 12:05 -0700 |
| Message-ID | <i6osukputnb0h683ek9ak4qomh3fhlah3s@4ax.com> |
| In reply to | #743349 |
On Sat, 25 Apr 2026 10:53:48 +0200, Jeroen Belleman <jeroen@nospam.please> wrote: >On 4/25/26 00:42, john larkin wrote: >> On Fri, 24 Apr 2026 22:23:32 +0200, Jeroen Belleman >> <jeroen@nospam.please> wrote: >> >>> On 4/24/26 18:43, Don wrote: >>>> john larkin wrote: >>>>> john larkin wrote: >>>>>> Don wrote: >>>>>>> john larkin wrote: >>>>>>>> Don wrote: >>>>>>>>> john larkin wrote: >>>>>>>>>> john larkin wrote: >>>>>>>>>>> Don wrote: >>>>>>>>>>>> Don wrote: >>>>>>>>>>>>> Recent thread topic transitioned to a tentative opinion on a work-in- >>>>>>>>>>>>> progress webpage: >>>>>>>>>>>>> >>>>>>>>>>>>> <https://crcomp.net/ledfilament/index.php> >>>>>>>>>>>>> >>>>>>>>>>>>> Radiography imparts interesting insight. Second opinions welcome! >>>>>>>>>>>>> The current waveform flopped. Any advice on how to use a Fluke >>>>>>>>>>>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >>>>>>>>>>>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on >>>>>>>>>>>>> the current probe? >>>>>>>>>>>> >>>>>>>>>>>> Alright you guys, a couple of current curve images are now available on >>>>>>>>>>>> the webpage. For the present case, in regards to the probe's "P2 < P1" >>>>>>>>>>>> orientation decal, P1 designates Line while P2 indicates Neutral. >>>>>>>>>>>> The probe provides a sharper, cleaner curve compared to the >>>>>>>>>>>> resistor. Both curves illustrate how the silicon filament primarily >>>>>>>>>>>> presents itself as a capacitive load. >>>>>>>>>>>> The filament's high voltage combined with its low amperage degrades >>>>>>>>>>>> resistor curve quality. It took a 10 M ohm resistive current sensor for >>>>>>>>>>>> the half-wave rectification effect to become visible. >>>>>>>>>>>> The probe curve's mostly blue trace shows the peak-to-peak Line >>>>>>>>>>>> voltage. It's used to properly trigger the scope. (Perhaps the scope's >>>>>>>>>>>> line trigger accomplishes the same result with less effort?) The probe >>>>>>>>>>>> curve's mostly green trace shows the current, with peaks and valleys >>>>>>>>>>>> created by half-wave rectification at each end of the filament. >>>>>>>>>>>> The current curve is set to 2mV per division. Does anyone know how >>>>>>>>>>>> to transpose it to mA? >>>>>>>>>>> >>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>> >>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>> >>>>>>>>>>> Unless one of the thingies on the end is a cap. A DC curve would >>>>>>>>>>> resolve that. >>>>>>>>>>> >>>>>>>>>>> A thermal image would be interesting too. >>>>>>>>>>> >>>>>>>>>> No, it lights up with DC, so there's no series cap. >>>>>>>>> >>>>>>>>> ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>> voltage trace, so the filament must present a capacitive load. >>>>>>>>> A silicon device that presents a capactive load is different from >>>>>>>>> a series capacitor: >>>>>>>>> >>>>>>>>> COB LEDs present capacitive loads through parasitic capacitances >>>>>>>>> inherent to their densely packed chip-on-board structure. These >>>>>>>>> capacitances arise between closely spaced LED dies, bonding >>>>>>>>> wires, and the substrate, affecting driver circuits during >>>>>>>>> switching. >>>>>>>> >>>>>>>> Since the current probe waveform is so different from the one that >>>>>>>> uses a resistor, one must be wrong, or likely both. >>>>>>>> >>>>>>>> Stray capacitances are at least six orders of magnitude from causing >>>>>>>> the phase shift that you are seeing. >>>>>>> >>>>>>> You're wrong, no doubt about it. Stray capacitance caused my problem. >>>>>>> And your sweeping generality at this juncture led me to question my >>>>>>> correct quantitative instincts. >>>>>>> >>>>>>> "ELI the ICE man. The trace of the current curve clearly leads the >>>>>>> voltage trace" leads to the correct solution. >>>>>>> >>>>>>> Hint: stray capacitance originates from more than one source. >>>>>> >>>>>> Probably the biggest capacitance is the LEDs themselves. >>>>> >>>>> Or the rectifier diodes. But still not much c. >>>>> >>>>> Measure it. >>>>>> >>>>>> If you used a sensible value current shunt resistor - ohms and not >>>>>> megohms - the effects of the capacitance would be invisible with 60 Hz >>>>>> excitation. >>>>>> >>>>>> Measure the capacitance and do the math. Or Spice it. >>>>>> >>>>>> "ELI the ICE man" is not quantitative. >>>> >>>> OK, We'll do it your quantitative way. Stray capacitance is at least six >>>> orders of magnitude higher than what you imagine. Because the biggest >>>> capacitance does not originate with the filament. >>>> >>>> There's no need to goof with a shunt resistor when an accurate current >>>> probe measurement is already available: >>>> >>>> <https://crcomp.net/ledfilament/curveprobe.png> >>>> >>>> It shows you everything you need to do your own math. Show me your >>>> math and I'll included on my webpage, with your permission. >> >> Iron-core current transformers get very nonlinear at low currents. The >> magnetic domains get sticky. You showed a gigantic CT. >> >>>> >>>> Hint for people who still don't see the light (so to speak): Bob Pease >>>> said, "My favorite programming language is solder." On a related note, >>>> Pease passionately hated one piece in particular, amid the equipment >>>> found in an electronic lab. >>>> >>>> Danke, >>>> >>>> -- >>>> 73, Don, WD7Q veritas _|_ >>>> liberabit | >>>> https://www.qsl.net/wd7q vos | >>>> >>> >>> This still doesn't make sense, but you piqued me enough to make >>> me do my own measurement. I don't see any phase shift between >>> voltage and current, although the power factor is certainly far >>>from unity. You can see my results here: >>> <https://cern.ch/jeroen/LEDstring>. >>> >>> Jeroen Belleman >> >> >> Was the curve on the left done at DC? > >No, it's the same data. I just plot I versus V. It's a bit >noisy; I should have filtered it a bit. > >> Why is your voltage waveform flat-topped? At 100 volts? >> >> At 30 mA, your 1K resistor drops 30 volts. So the "Voltage" connector >> doesn't represent the voltage seen by the DUT. > >True, the voltage recording is distorted by the superimposed current >curve. That also explains the flat top. I could use a smaller >current sense resistor, or compensate for its voltge drop. I don't understand the flat top. You are presumably scoping the 240 volt AC line. > >> >> And does the "Voltage" connector go straight into a scope channel? No >> probe? > >I used regular 1:10 scope probes. > >> Your current waveform does have about the right shape and timing. No >> time lags. >> >> The x-rayed COB seems to have a 4-diode bridge rectifier, two >> resistors, and one string of LEDs. That is more cost effective than >> having two strings, twice as many LEDs, each on half the time. > >True. I expected my strings to be similar to Don's, but they weren't. > >> John Larkin >> Highland Tech Glen Canyon Design Center >> Lunatic Fringe Electronics > >Exposing in some detail what I did lends people the ability to >really understand what's going on and to propose improvements. >Don's measurements leave too much room for mystery. > >Jeroen Belleman > > A 240-volt led lamp will be different from 120. It might have half-wave rectification. And I'd expect lots of different light bulbs. Some have electronics in the base. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | piglet <erichpwagner@hotmail.com> |
|---|---|
| Date | 2026-04-26 19:20 +0000 |
| Message-ID | <10slohs$1qkp7$1@dont-email.me> |
| In reply to | #743429 |
john larkin <jl@glen--canyon.com> wrote: > On Sat, 25 Apr 2026 10:53:48 +0200, Jeroen Belleman > <jeroen@nospam.please> wrote: > >> On 4/25/26 00:42, john larkin wrote: >>> On Fri, 24 Apr 2026 22:23:32 +0200, Jeroen Belleman >>> <jeroen@nospam.please> wrote: >>> >>>> On 4/24/26 18:43, Don wrote: >>>>> john larkin wrote: >>>>>> john larkin wrote: >>>>>>> Don wrote: >>>>>>>> john larkin wrote: >>>>>>>>> Don wrote: >>>>>>>>>> john larkin wrote: >>>>>>>>>>> john larkin wrote: >>>>>>>>>>>> Don wrote: >>>>>>>>>>>>> Don wrote: >>>>>>>>>>>>>> Recent thread topic transitioned to a tentative opinion on a work-in- >>>>>>>>>>>>>> progress webpage: >>>>>>>>>>>>>> >>>>>>>>>>>>>> <https://crcomp.net/ledfilament/index.php> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Radiography imparts interesting insight. Second opinions welcome! >>>>>>>>>>>>>> The current waveform flopped. Any advice on how to use a Fluke >>>>>>>>>>>>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >>>>>>>>>>>>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on >>>>>>>>>>>>>> the current probe? >>>>>>>>>>>>> >>>>>>>>>>>>> Alright you guys, a couple of current curve images are now available on >>>>>>>>>>>>> the webpage. For the present case, in regards to the probe's "P2 < P1" >>>>>>>>>>>>> orientation decal, P1 designates Line while P2 indicates Neutral. >>>>>>>>>>>>> The probe provides a sharper, cleaner curve compared to the >>>>>>>>>>>>> resistor. Both curves illustrate how the silicon filament primarily >>>>>>>>>>>>> presents itself as a capacitive load. >>>>>>>>>>>>> The filament's high voltage combined with its low amperage degrades >>>>>>>>>>>>> resistor curve quality. It took a 10 M ohm resistive current sensor for >>>>>>>>>>>>> the half-wave rectification effect to become visible. >>>>>>>>>>>>> The probe curve's mostly blue trace shows the peak-to-peak Line >>>>>>>>>>>>> voltage. It's used to properly trigger the scope. (Perhaps the scope's >>>>>>>>>>>>> line trigger accomplishes the same result with less effort?) The probe >>>>>>>>>>>>> curve's mostly green trace shows the current, with peaks and valleys >>>>>>>>>>>>> created by half-wave rectification at each end of the filament. >>>>>>>>>>>>> The current curve is set to 2mV per division. Does anyone know how >>>>>>>>>>>>> to transpose it to mA? >>>>>>>>>>>> >>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>> >>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>> >>>>>>>>>>>> Unless one of the thingies on the end is a cap. A DC curve would >>>>>>>>>>>> resolve that. >>>>>>>>>>>> >>>>>>>>>>>> A thermal image would be interesting too. >>>>>>>>>>>> >>>>>>>>>>> No, it lights up with DC, so there's no series cap. >>>>>>>>>> >>>>>>>>>> ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>>> voltage trace, so the filament must present a capacitive load. >>>>>>>>>> A silicon device that presents a capactive load is different from >>>>>>>>>> a series capacitor: >>>>>>>>>> >>>>>>>>>> COB LEDs present capacitive loads through parasitic capacitances >>>>>>>>>> inherent to their densely packed chip-on-board structure. These >>>>>>>>>> capacitances arise between closely spaced LED dies, bonding >>>>>>>>>> wires, and the substrate, affecting driver circuits during >>>>>>>>>> switching. >>>>>>>>> >>>>>>>>> Since the current probe waveform is so different from the one that >>>>>>>>> uses a resistor, one must be wrong, or likely both. >>>>>>>>> >>>>>>>>> Stray capacitances are at least six orders of magnitude from causing >>>>>>>>> the phase shift that you are seeing. >>>>>>>> >>>>>>>> You're wrong, no doubt about it. Stray capacitance caused my problem. >>>>>>>> And your sweeping generality at this juncture led me to question my >>>>>>>> correct quantitative instincts. >>>>>>>> >>>>>>>> "ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>> voltage trace" leads to the correct solution. >>>>>>>> >>>>>>>> Hint: stray capacitance originates from more than one source. >>>>>>> >>>>>>> Probably the biggest capacitance is the LEDs themselves. >>>>>> >>>>>> Or the rectifier diodes. But still not much c. >>>>>> >>>>>> Measure it. >>>>>>> >>>>>>> If you used a sensible value current shunt resistor - ohms and not >>>>>>> megohms - the effects of the capacitance would be invisible with 60 Hz >>>>>>> excitation. >>>>>>> >>>>>>> Measure the capacitance and do the math. Or Spice it. >>>>>>> >>>>>>> "ELI the ICE man" is not quantitative. >>>>> >>>>> OK, We'll do it your quantitative way. Stray capacitance is at least six >>>>> orders of magnitude higher than what you imagine. Because the biggest >>>>> capacitance does not originate with the filament. >>>>> >>>>> There's no need to goof with a shunt resistor when an accurate current >>>>> probe measurement is already available: >>>>> >>>>> <https://crcomp.net/ledfilament/curveprobe.png> >>>>> >>>>> It shows you everything you need to do your own math. Show me your >>>>> math and I'll included on my webpage, with your permission. >>> >>> Iron-core current transformers get very nonlinear at low currents. The >>> magnetic domains get sticky. You showed a gigantic CT. >>> >>>>> >>>>> Hint for people who still don't see the light (so to speak): Bob Pease >>>>> said, "My favorite programming language is solder." On a related note, >>>>> Pease passionately hated one piece in particular, amid the equipment >>>>> found in an electronic lab. >>>>> >>>>> Danke, >>>>> >>>>> -- >>>>> 73, Don, WD7Q veritas _|_ >>>>> liberabit | >>>>> https://www.qsl.net/wd7q vos | >>>>> >>>> >>>> This still doesn't make sense, but you piqued me enough to make >>>> me do my own measurement. I don't see any phase shift between >>>> voltage and current, although the power factor is certainly far >>>> from unity. You can see my results here: >>>> <https://cern.ch/jeroen/LEDstring>. >>>> >>>> Jeroen Belleman >>> >>> >>> Was the curve on the left done at DC? >> >> No, it's the same data. I just plot I versus V. It's a bit >> noisy; I should have filtered it a bit. >> >>> Why is your voltage waveform flat-topped? At 100 volts? >>> >>> At 30 mA, your 1K resistor drops 30 volts. So the "Voltage" connector >>> doesn't represent the voltage seen by the DUT. >> >> True, the voltage recording is distorted by the superimposed current >> curve. That also explains the flat top. I could use a smaller >> current sense resistor, or compensate for its voltge drop. > > I don't understand the flat top. You are presumably scoping the 240 > volt AC line. > >> >>> >>> And does the "Voltage" connector go straight into a scope channel? No >>> probe? >> >> I used regular 1:10 scope probes. >> >>> Your current waveform does have about the right shape and timing. No >>> time lags. >>> >>> The x-rayed COB seems to have a 4-diode bridge rectifier, two >>> resistors, and one string of LEDs. That is more cost effective than >>> having two strings, twice as many LEDs, each on half the time. >> >> True. I expected my strings to be similar to Don's, but they weren't. >> >>> John Larkin >>> Highland Tech Glen Canyon Design Center >>> Lunatic Fringe Electronics >> >> Exposing in some detail what I did lends people the ability to >> really understand what's going on and to propose improvements. >> Don's measurements leave too much room for mystery. >> >> Jeroen Belleman >> >> > > A 240-volt led lamp will be different from 120. It might have > half-wave rectification. > > And I'd expect lots of different light bulbs. Some have electronics in > the base. > > > John Larkin > Highland Tech Glen Canyon Design Center > Lunatic Fringe Electronics > Most mains is now slightly flat topped from the huge number of SMPSUs in use and utility transformers running into mild saturation near peaks. -- piglet
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-04-27 12:49 -0700 |
| Message-ID | <9vevuktof8lm5uan60nv1it22liecoo2qq@4ax.com> |
| In reply to | #743432 |
On Sun, 26 Apr 2026 19:20:28 -0000 (UTC), piglet <erichpwagner@hotmail.com> wrote: >john larkin <jl@glen--canyon.com> wrote: >> On Sat, 25 Apr 2026 10:53:48 +0200, Jeroen Belleman >> <jeroen@nospam.please> wrote: >> >>> On 4/25/26 00:42, john larkin wrote: >>>> On Fri, 24 Apr 2026 22:23:32 +0200, Jeroen Belleman >>>> <jeroen@nospam.please> wrote: >>>> >>>>> On 4/24/26 18:43, Don wrote: >>>>>> john larkin wrote: >>>>>>> john larkin wrote: >>>>>>>> Don wrote: >>>>>>>>> john larkin wrote: >>>>>>>>>> Don wrote: >>>>>>>>>>> john larkin wrote: >>>>>>>>>>>> john larkin wrote: >>>>>>>>>>>>> Don wrote: >>>>>>>>>>>>>> Don wrote: >>>>>>>>>>>>>>> Recent thread topic transitioned to a tentative opinion on a work-in- >>>>>>>>>>>>>>> progress webpage: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> <https://crcomp.net/ledfilament/index.php> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Radiography imparts interesting insight. Second opinions welcome! >>>>>>>>>>>>>>> The current waveform flopped. Any advice on how to use a Fluke >>>>>>>>>>>>>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >>>>>>>>>>>>>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on >>>>>>>>>>>>>>> the current probe? >>>>>>>>>>>>>> >>>>>>>>>>>>>> Alright you guys, a couple of current curve images are now available on >>>>>>>>>>>>>> the webpage. For the present case, in regards to the probe's "P2 < P1" >>>>>>>>>>>>>> orientation decal, P1 designates Line while P2 indicates Neutral. >>>>>>>>>>>>>> The probe provides a sharper, cleaner curve compared to the >>>>>>>>>>>>>> resistor. Both curves illustrate how the silicon filament primarily >>>>>>>>>>>>>> presents itself as a capacitive load. >>>>>>>>>>>>>> The filament's high voltage combined with its low amperage degrades >>>>>>>>>>>>>> resistor curve quality. It took a 10 M ohm resistive current sensor for >>>>>>>>>>>>>> the half-wave rectification effect to become visible. >>>>>>>>>>>>>> The probe curve's mostly blue trace shows the peak-to-peak Line >>>>>>>>>>>>>> voltage. It's used to properly trigger the scope. (Perhaps the scope's >>>>>>>>>>>>>> line trigger accomplishes the same result with less effort?) The probe >>>>>>>>>>>>>> curve's mostly green trace shows the current, with peaks and valleys >>>>>>>>>>>>>> created by half-wave rectification at each end of the filament. >>>>>>>>>>>>>> The current curve is set to 2mV per division. Does anyone know how >>>>>>>>>>>>>> to transpose it to mA? >>>>>>>>>>>>> >>>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>>> >>>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>>> >>>>>>>>>>>>> Unless one of the thingies on the end is a cap. A DC curve would >>>>>>>>>>>>> resolve that. >>>>>>>>>>>>> >>>>>>>>>>>>> A thermal image would be interesting too. >>>>>>>>>>>>> >>>>>>>>>>>> No, it lights up with DC, so there's no series cap. >>>>>>>>>>> >>>>>>>>>>> ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>>>> voltage trace, so the filament must present a capacitive load. >>>>>>>>>>> A silicon device that presents a capactive load is different from >>>>>>>>>>> a series capacitor: >>>>>>>>>>> >>>>>>>>>>> COB LEDs present capacitive loads through parasitic capacitances >>>>>>>>>>> inherent to their densely packed chip-on-board structure. These >>>>>>>>>>> capacitances arise between closely spaced LED dies, bonding >>>>>>>>>>> wires, and the substrate, affecting driver circuits during >>>>>>>>>>> switching. >>>>>>>>>> >>>>>>>>>> Since the current probe waveform is so different from the one that >>>>>>>>>> uses a resistor, one must be wrong, or likely both. >>>>>>>>>> >>>>>>>>>> Stray capacitances are at least six orders of magnitude from causing >>>>>>>>>> the phase shift that you are seeing. >>>>>>>>> >>>>>>>>> You're wrong, no doubt about it. Stray capacitance caused my problem. >>>>>>>>> And your sweeping generality at this juncture led me to question my >>>>>>>>> correct quantitative instincts. >>>>>>>>> >>>>>>>>> "ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>> voltage trace" leads to the correct solution. >>>>>>>>> >>>>>>>>> Hint: stray capacitance originates from more than one source. >>>>>>>> >>>>>>>> Probably the biggest capacitance is the LEDs themselves. >>>>>>> >>>>>>> Or the rectifier diodes. But still not much c. >>>>>>> >>>>>>> Measure it. >>>>>>>> >>>>>>>> If you used a sensible value current shunt resistor - ohms and not >>>>>>>> megohms - the effects of the capacitance would be invisible with 60 Hz >>>>>>>> excitation. >>>>>>>> >>>>>>>> Measure the capacitance and do the math. Or Spice it. >>>>>>>> >>>>>>>> "ELI the ICE man" is not quantitative. >>>>>> >>>>>> OK, We'll do it your quantitative way. Stray capacitance is at least six >>>>>> orders of magnitude higher than what you imagine. Because the biggest >>>>>> capacitance does not originate with the filament. >>>>>> >>>>>> There's no need to goof with a shunt resistor when an accurate current >>>>>> probe measurement is already available: >>>>>> >>>>>> <https://crcomp.net/ledfilament/curveprobe.png> >>>>>> >>>>>> It shows you everything you need to do your own math. Show me your >>>>>> math and I'll included on my webpage, with your permission. >>>> >>>> Iron-core current transformers get very nonlinear at low currents. The >>>> magnetic domains get sticky. You showed a gigantic CT. >>>> >>>>>> >>>>>> Hint for people who still don't see the light (so to speak): Bob Pease >>>>>> said, "My favorite programming language is solder." On a related note, >>>>>> Pease passionately hated one piece in particular, amid the equipment >>>>>> found in an electronic lab. >>>>>> >>>>>> Danke, >>>>>> >>>>>> -- >>>>>> 73, Don, WD7Q veritas _|_ >>>>>> liberabit | >>>>>> https://www.qsl.net/wd7q vos | >>>>>> >>>>> >>>>> This still doesn't make sense, but you piqued me enough to make >>>>> me do my own measurement. I don't see any phase shift between >>>>> voltage and current, although the power factor is certainly far >>>>> from unity. You can see my results here: >>>>> <https://cern.ch/jeroen/LEDstring>. >>>>> >>>>> Jeroen Belleman >>>> >>>> >>>> Was the curve on the left done at DC? >>> >>> No, it's the same data. I just plot I versus V. It's a bit >>> noisy; I should have filtered it a bit. >>> >>>> Why is your voltage waveform flat-topped? At 100 volts? >>>> >>>> At 30 mA, your 1K resistor drops 30 volts. So the "Voltage" connector >>>> doesn't represent the voltage seen by the DUT. >>> >>> True, the voltage recording is distorted by the superimposed current >>> curve. That also explains the flat top. I could use a smaller >>> current sense resistor, or compensate for its voltge drop. >> >> I don't understand the flat top. You are presumably scoping the 240 >> volt AC line. >> >>> >>>> >>>> And does the "Voltage" connector go straight into a scope channel? No >>>> probe? >>> >>> I used regular 1:10 scope probes. >>> >>>> Your current waveform does have about the right shape and timing. No >>>> time lags. >>>> >>>> The x-rayed COB seems to have a 4-diode bridge rectifier, two >>>> resistors, and one string of LEDs. That is more cost effective than >>>> having two strings, twice as many LEDs, each on half the time. >>> >>> True. I expected my strings to be similar to Don's, but they weren't. >>> >>>> John Larkin >>>> Highland Tech Glen Canyon Design Center >>>> Lunatic Fringe Electronics >>> >>> Exposing in some detail what I did lends people the ability to >>> really understand what's going on and to propose improvements. >>> Don's measurements leave too much room for mystery. >>> >>> Jeroen Belleman >>> >>> >> >> A 240-volt led lamp will be different from 120. It might have >> half-wave rectification. >> >> And I'd expect lots of different light bulbs. Some have electronics in >> the base. >> >> >> John Larkin >> Highland Tech Glen Canyon Design Center >> Lunatic Fringe Electronics >> > >Most mains is now slightly flat topped from the huge number of SMPSUs in >use and utility transformers running into mild saturation near peaks. Here's the AC line here: https://www.dropbox.com/scl/fi/lx0i5c2qezi0d4kd1xzea/AC_Line_Chenery.jpg?rlkey=ngdqe6j3uphwqrb2gex4buoli&raw=1 It's flatter than I remember from past tests. This is the AC hot, relative to the grounded scope. But there isn't much on the neutral wire, so the waveform is about right. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-04-27 17:04 +1000 |
| Message-ID | <10sn1qc$25nnq$2@dont-email.me> |
| In reply to | #743429 |
On 27/04/2026 5:05 am, john larkin wrote: > On Sat, 25 Apr 2026 10:53:48 +0200, Jeroen Belleman > <jeroen@nospam.please> wrote: > >> On 4/25/26 00:42, john larkin wrote: >>> On Fri, 24 Apr 2026 22:23:32 +0200, Jeroen Belleman >>> <jeroen@nospam.please> wrote: >>> >>>> On 4/24/26 18:43, Don wrote: >>>>> john larkin wrote: >>>>>> john larkin wrote: >>>>>>> Don wrote: >>>>>>>> john larkin wrote: >>>>>>>>> Don wrote: >>>>>>>>>> john larkin wrote: >>>>>>>>>>> john larkin wrote: >>>>>>>>>>>> Don wrote: >>>>>>>>>>>>> Don wrote: >>>>>>>>>>>>>> Recent thread topic transitioned to a tentative opinion on a work-in- >>>>>>>>>>>>>> progress webpage: >>>>>>>>>>>>>> >>>>>>>>>>>>>> <https://crcomp.net/ledfilament/index.php> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Radiography imparts interesting insight. Second opinions welcome! >>>>>>>>>>>>>> The current waveform flopped. Any advice on how to use a Fluke >>>>>>>>>>>>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >>>>>>>>>>>>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on >>>>>>>>>>>>>> the current probe? >>>>>>>>>>>>> >>>>>>>>>>>>> Alright you guys, a couple of current curve images are now available on >>>>>>>>>>>>> the webpage. For the present case, in regards to the probe's "P2 < P1" >>>>>>>>>>>>> orientation decal, P1 designates Line while P2 indicates Neutral. >>>>>>>>>>>>> The probe provides a sharper, cleaner curve compared to the >>>>>>>>>>>>> resistor. Both curves illustrate how the silicon filament primarily >>>>>>>>>>>>> presents itself as a capacitive load. >>>>>>>>>>>>> The filament's high voltage combined with its low amperage degrades >>>>>>>>>>>>> resistor curve quality. It took a 10 M ohm resistive current sensor for >>>>>>>>>>>>> the half-wave rectification effect to become visible. >>>>>>>>>>>>> The probe curve's mostly blue trace shows the peak-to-peak Line >>>>>>>>>>>>> voltage. It's used to properly trigger the scope. (Perhaps the scope's >>>>>>>>>>>>> line trigger accomplishes the same result with less effort?) The probe >>>>>>>>>>>>> curve's mostly green trace shows the current, with peaks and valleys >>>>>>>>>>>>> created by half-wave rectification at each end of the filament. >>>>>>>>>>>>> The current curve is set to 2mV per division. Does anyone know how >>>>>>>>>>>>> to transpose it to mA? >>>>>>>>>>>> >>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>> >>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>> >>>>>>>>>>>> Unless one of the thingies on the end is a cap. A DC curve would >>>>>>>>>>>> resolve that. >>>>>>>>>>>> >>>>>>>>>>>> A thermal image would be interesting too. >>>>>>>>>>>> >>>>>>>>>>> No, it lights up with DC, so there's no series cap. >>>>>>>>>> >>>>>>>>>> ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>>> voltage trace, so the filament must present a capacitive load. >>>>>>>>>> A silicon device that presents a capactive load is different from >>>>>>>>>> a series capacitor: >>>>>>>>>> >>>>>>>>>> COB LEDs present capacitive loads through parasitic capacitances >>>>>>>>>> inherent to their densely packed chip-on-board structure. These >>>>>>>>>> capacitances arise between closely spaced LED dies, bonding >>>>>>>>>> wires, and the substrate, affecting driver circuits during >>>>>>>>>> switching. >>>>>>>>> >>>>>>>>> Since the current probe waveform is so different from the one that >>>>>>>>> uses a resistor, one must be wrong, or likely both. >>>>>>>>> >>>>>>>>> Stray capacitances are at least six orders of magnitude from causing >>>>>>>>> the phase shift that you are seeing. >>>>>>>> >>>>>>>> You're wrong, no doubt about it. Stray capacitance caused my problem. >>>>>>>> And your sweeping generality at this juncture led me to question my >>>>>>>> correct quantitative instincts. >>>>>>>> >>>>>>>> "ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>> voltage trace" leads to the correct solution. >>>>>>>> >>>>>>>> Hint: stray capacitance originates from more than one source. >>>>>>> >>>>>>> Probably the biggest capacitance is the LEDs themselves. >>>>>> >>>>>> Or the rectifier diodes. But still not much c. >>>>>> >>>>>> Measure it. >>>>>>> >>>>>>> If you used a sensible value current shunt resistor - ohms and not >>>>>>> megohms - the effects of the capacitance would be invisible with 60 Hz >>>>>>> excitation. >>>>>>> >>>>>>> Measure the capacitance and do the math. Or Spice it. >>>>>>> >>>>>>> "ELI the ICE man" is not quantitative. >>>>> >>>>> OK, We'll do it your quantitative way. Stray capacitance is at least six >>>>> orders of magnitude higher than what you imagine. Because the biggest >>>>> capacitance does not originate with the filament. >>>>> >>>>> There's no need to goof with a shunt resistor when an accurate current >>>>> probe measurement is already available: >>>>> >>>>> <https://crcomp.net/ledfilament/curveprobe.png> >>>>> >>>>> It shows you everything you need to do your own math. Show me your >>>>> math and I'll included on my webpage, with your permission. >>> >>> Iron-core current transformers get very nonlinear at low currents. The >>> magnetic domains get sticky. You showed a gigantic CT. >>> >>>>> >>>>> Hint for people who still don't see the light (so to speak): Bob Pease >>>>> said, "My favorite programming language is solder." On a related note, >>>>> Pease passionately hated one piece in particular, amid the equipment >>>>> found in an electronic lab. >>>>> >>>>> Danke, >>>>> >>>>> -- >>>>> 73, Don, WD7Q veritas _|_ >>>>> liberabit | >>>>> https://www.qsl.net/wd7q vos | >>>>> >>>> >>>> This still doesn't make sense, but you piqued me enough to make >>>> me do my own measurement. I don't see any phase shift between >>>> voltage and current, although the power factor is certainly far >>> >from unity. You can see my results here: >>>> <https://cern.ch/jeroen/LEDstring>. >>>> >>>> Jeroen Belleman >>> >>> >>> Was the curve on the left done at DC? >> >> No, it's the same data. I just plot I versus V. It's a bit >> noisy; I should have filtered it a bit. >> >>> Why is your voltage waveform flat-topped? At 100 volts? >>> >>> At 30 mA, your 1K resistor drops 30 volts. So the "Voltage" connector >>> doesn't represent the voltage seen by the DUT. >> >> True, the voltage recording is distorted by the superimposed current >> curve. That also explains the flat top. I could use a smaller >> current sense resistor, or compensate for its voltge drop. > > I don't understand the flat top. You are presumably scoping the 240 > volt AC line. > >> >>> >>> And does the "Voltage" connector go straight into a scope channel? No >>> probe? >> >> I used regular 1:10 scope probes. >> >>> Your current waveform does have about the right shape and timing. No >>> time lags. >>> >>> The x-rayed COB seems to have a 4-diode bridge rectifier, two >>> resistors, and one string of LEDs. That is more cost effective than >>> having two strings, twice as many LEDs, each on half the time. >> >> True. I expected my strings to be similar to Don's, but they weren't. >> >>> John Larkin >>> Highland Tech Glen Canyon Design Center >>> Lunatic Fringe Electronics >> >> Exposing in some detail what I did lends people the ability to >> really understand what's going on and to propose improvements. >> Don's measurements leave too much room for mystery. >> >> Jeroen Belleman >> >> > > A 240-volt led lamp will be different from 120. It might have > half-wave rectification. Why? > And I'd expect lots of different light bulbs. Some have electronics in > the base. Any "light bulb" that relies on LEDs includes lots of electronics. There's no particular reason to put it all in the base. My flat came with lots of Philips tungsten halogen spot lights. One of them ended close to a temperature sensor for the buildings revised fire control system, so I replaced the conical plug-in bulb with a LED based plug-in equivalent, which ran a lot cooler. The base of the replacement wasn't transparent but it wouldn't have offered much space for electronics. -- Bill Sloman, Sydney
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| From | Jeroen Belleman <jeroen@nospam.please> |
|---|---|
| Date | 2026-04-27 10:59 +0200 |
| Message-ID | <10sn8h8$27og9$1@dont-email.me> |
| In reply to | #743429 |
On 4/26/26 21:05, john larkin wrote: > On Sat, 25 Apr 2026 10:53:48 +0200, Jeroen Belleman > <jeroen@nospam.please> wrote: > >> On 4/25/26 00:42, john larkin wrote: >>> On Fri, 24 Apr 2026 22:23:32 +0200, Jeroen Belleman >>> <jeroen@nospam.please> wrote: >>> >>>> On 4/24/26 18:43, Don wrote: >>>>> john larkin wrote: >>>>>> john larkin wrote: >>>>>>> Don wrote: >>>>>>>> john larkin wrote: >>>>>>>>> Don wrote: >>>>>>>>>> john larkin wrote: >>>>>>>>>>> john larkin wrote: >>>>>>>>>>>> Don wrote: >>>>>>>>>>>>> Don wrote: >>>>>>>>>>>>>> Recent thread topic transitioned to a tentative opinion on a work-in- >>>>>>>>>>>>>> progress webpage: >>>>>>>>>>>>>> >>>>>>>>>>>>>> <https://crcomp.net/ledfilament/index.php> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Radiography imparts interesting insight. Second opinions welcome! >>>>>>>>>>>>>> The current waveform flopped. Any advice on how to use a Fluke >>>>>>>>>>>>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >>>>>>>>>>>>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on >>>>>>>>>>>>>> the current probe? >>>>>>>>>>>>> >>>>>>>>>>>>> Alright you guys, a couple of current curve images are now available on >>>>>>>>>>>>> the webpage. For the present case, in regards to the probe's "P2 < P1" >>>>>>>>>>>>> orientation decal, P1 designates Line while P2 indicates Neutral. >>>>>>>>>>>>> The probe provides a sharper, cleaner curve compared to the >>>>>>>>>>>>> resistor. Both curves illustrate how the silicon filament primarily >>>>>>>>>>>>> presents itself as a capacitive load. >>>>>>>>>>>>> The filament's high voltage combined with its low amperage degrades >>>>>>>>>>>>> resistor curve quality. It took a 10 M ohm resistive current sensor for >>>>>>>>>>>>> the half-wave rectification effect to become visible. >>>>>>>>>>>>> The probe curve's mostly blue trace shows the peak-to-peak Line >>>>>>>>>>>>> voltage. It's used to properly trigger the scope. (Perhaps the scope's >>>>>>>>>>>>> line trigger accomplishes the same result with less effort?) The probe >>>>>>>>>>>>> curve's mostly green trace shows the current, with peaks and valleys >>>>>>>>>>>>> created by half-wave rectification at each end of the filament. >>>>>>>>>>>>> The current curve is set to 2mV per division. Does anyone know how >>>>>>>>>>>>> to transpose it to mA? >>>>>>>>>>>> >>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>> >>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>> >>>>>>>>>>>> Unless one of the thingies on the end is a cap. A DC curve would >>>>>>>>>>>> resolve that. >>>>>>>>>>>> >>>>>>>>>>>> A thermal image would be interesting too. >>>>>>>>>>>> >>>>>>>>>>> No, it lights up with DC, so there's no series cap. >>>>>>>>>> >>>>>>>>>> ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>>> voltage trace, so the filament must present a capacitive load. >>>>>>>>>> A silicon device that presents a capactive load is different from >>>>>>>>>> a series capacitor: >>>>>>>>>> >>>>>>>>>> COB LEDs present capacitive loads through parasitic capacitances >>>>>>>>>> inherent to their densely packed chip-on-board structure. These >>>>>>>>>> capacitances arise between closely spaced LED dies, bonding >>>>>>>>>> wires, and the substrate, affecting driver circuits during >>>>>>>>>> switching. >>>>>>>>> >>>>>>>>> Since the current probe waveform is so different from the one that >>>>>>>>> uses a resistor, one must be wrong, or likely both. >>>>>>>>> >>>>>>>>> Stray capacitances are at least six orders of magnitude from causing >>>>>>>>> the phase shift that you are seeing. >>>>>>>> >>>>>>>> You're wrong, no doubt about it. Stray capacitance caused my problem. >>>>>>>> And your sweeping generality at this juncture led me to question my >>>>>>>> correct quantitative instincts. >>>>>>>> >>>>>>>> "ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>> voltage trace" leads to the correct solution. >>>>>>>> >>>>>>>> Hint: stray capacitance originates from more than one source. >>>>>>> >>>>>>> Probably the biggest capacitance is the LEDs themselves. >>>>>> >>>>>> Or the rectifier diodes. But still not much c. >>>>>> >>>>>> Measure it. >>>>>>> >>>>>>> If you used a sensible value current shunt resistor - ohms and not >>>>>>> megohms - the effects of the capacitance would be invisible with 60 Hz >>>>>>> excitation. >>>>>>> >>>>>>> Measure the capacitance and do the math. Or Spice it. >>>>>>> >>>>>>> "ELI the ICE man" is not quantitative. >>>>> >>>>> OK, We'll do it your quantitative way. Stray capacitance is at least six >>>>> orders of magnitude higher than what you imagine. Because the biggest >>>>> capacitance does not originate with the filament. >>>>> >>>>> There's no need to goof with a shunt resistor when an accurate current >>>>> probe measurement is already available: >>>>> >>>>> <https://crcomp.net/ledfilament/curveprobe.png> >>>>> >>>>> It shows you everything you need to do your own math. Show me your >>>>> math and I'll included on my webpage, with your permission. >>> >>> Iron-core current transformers get very nonlinear at low currents. The >>> magnetic domains get sticky. You showed a gigantic CT. >>> >>>>> >>>>> Hint for people who still don't see the light (so to speak): Bob Pease >>>>> said, "My favorite programming language is solder." On a related note, >>>>> Pease passionately hated one piece in particular, amid the equipment >>>>> found in an electronic lab. >>>>> >>>>> Danke, >>>>> >>>>> -- >>>>> 73, Don, WD7Q veritas _|_ >>>>> liberabit | >>>>> https://www.qsl.net/wd7q vos | >>>>> >>>> >>>> This still doesn't make sense, but you piqued me enough to make >>>> me do my own measurement. I don't see any phase shift between >>>> voltage and current, although the power factor is certainly far >>> >from unity. You can see my results here: >>>> <https://cern.ch/jeroen/LEDstring>. >>>> >>>> Jeroen Belleman >>> >>> >>> Was the curve on the left done at DC? >> >> No, it's the same data. I just plot I versus V. It's a bit >> noisy; I should have filtered it a bit. >> >>> Why is your voltage waveform flat-topped? At 100 volts? >>> >>> At 30 mA, your 1K resistor drops 30 volts. So the "Voltage" connector >>> doesn't represent the voltage seen by the DUT. >> >> True, the voltage recording is distorted by the superimposed current >> curve. That also explains the flat top. I could use a smaller >> current sense resistor, or compensate for its voltge drop. > > I don't understand the flat top. You are presumably scoping the 240 > volt AC line. My AC source is not straight mains. I value my life. Instead, I used a toy train variac transformer feeding a little 15VA mains transformer in reverse. Plenty of opportunities to distort the waveform. > >> >>> >>> And does the "Voltage" connector go straight into a scope channel? No >>> probe? >> >> I used regular 1:10 scope probes. >> >>> Your current waveform does have about the right shape and timing. No >>> time lags. >>> >>> The x-rayed COB seems to have a 4-diode bridge rectifier, two >>> resistors, and one string of LEDs. That is more cost effective than >>> having two strings, twice as many LEDs, each on half the time. >> >> True. I expected my strings to be similar to Don's, but they weren't. >> >>> John Larkin >>> Highland Tech Glen Canyon Design Center >>> Lunatic Fringe Electronics >> >> Exposing in some detail what I did lends people the ability to >> really understand what's going on and to propose improvements. >> Don's measurements leave too much room for mystery. >> >> Jeroen Belleman >> >> > > A 240-volt led lamp will be different from 120. It might have > half-wave rectification. > > And I'd expect lots of different light bulbs. Some have electronics in > the base. > > > John Larkin > Highland Tech Glen Canyon Design Center > Lunatic Fringe Electronics The LED strings I tested do indeed conduct only one way. There are some electronics in the base which I haven't yet looked at. Jeroen Belleman
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-04-27 08:11 -0700 |
| Message-ID | <lauuukljqdkr43n7pf5h3o6likeffq2pup@4ax.com> |
| In reply to | #743456 |
On Mon, 27 Apr 2026 10:59:20 +0200, Jeroen Belleman <jeroen@nospam.please> wrote: >On 4/26/26 21:05, john larkin wrote: >> On Sat, 25 Apr 2026 10:53:48 +0200, Jeroen Belleman >> <jeroen@nospam.please> wrote: >> >>> On 4/25/26 00:42, john larkin wrote: >>>> On Fri, 24 Apr 2026 22:23:32 +0200, Jeroen Belleman >>>> <jeroen@nospam.please> wrote: >>>> >>>>> On 4/24/26 18:43, Don wrote: >>>>>> john larkin wrote: >>>>>>> john larkin wrote: >>>>>>>> Don wrote: >>>>>>>>> john larkin wrote: >>>>>>>>>> Don wrote: >>>>>>>>>>> john larkin wrote: >>>>>>>>>>>> john larkin wrote: >>>>>>>>>>>>> Don wrote: >>>>>>>>>>>>>> Don wrote: >>>>>>>>>>>>>>> Recent thread topic transitioned to a tentative opinion on a work-in- >>>>>>>>>>>>>>> progress webpage: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> <https://crcomp.net/ledfilament/index.php> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Radiography imparts interesting insight. Second opinions welcome! >>>>>>>>>>>>>>> The current waveform flopped. Any advice on how to use a Fluke >>>>>>>>>>>>>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >>>>>>>>>>>>>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on >>>>>>>>>>>>>>> the current probe? >>>>>>>>>>>>>> >>>>>>>>>>>>>> Alright you guys, a couple of current curve images are now available on >>>>>>>>>>>>>> the webpage. For the present case, in regards to the probe's "P2 < P1" >>>>>>>>>>>>>> orientation decal, P1 designates Line while P2 indicates Neutral. >>>>>>>>>>>>>> The probe provides a sharper, cleaner curve compared to the >>>>>>>>>>>>>> resistor. Both curves illustrate how the silicon filament primarily >>>>>>>>>>>>>> presents itself as a capacitive load. >>>>>>>>>>>>>> The filament's high voltage combined with its low amperage degrades >>>>>>>>>>>>>> resistor curve quality. It took a 10 M ohm resistive current sensor for >>>>>>>>>>>>>> the half-wave rectification effect to become visible. >>>>>>>>>>>>>> The probe curve's mostly blue trace shows the peak-to-peak Line >>>>>>>>>>>>>> voltage. It's used to properly trigger the scope. (Perhaps the scope's >>>>>>>>>>>>>> line trigger accomplishes the same result with less effort?) The probe >>>>>>>>>>>>>> curve's mostly green trace shows the current, with peaks and valleys >>>>>>>>>>>>>> created by half-wave rectification at each end of the filament. >>>>>>>>>>>>>> The current curve is set to 2mV per division. Does anyone know how >>>>>>>>>>>>>> to transpose it to mA? >>>>>>>>>>>>> >>>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>>> >>>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>>> >>>>>>>>>>>>> Unless one of the thingies on the end is a cap. A DC curve would >>>>>>>>>>>>> resolve that. >>>>>>>>>>>>> >>>>>>>>>>>>> A thermal image would be interesting too. >>>>>>>>>>>>> >>>>>>>>>>>> No, it lights up with DC, so there's no series cap. >>>>>>>>>>> >>>>>>>>>>> ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>>>> voltage trace, so the filament must present a capacitive load. >>>>>>>>>>> A silicon device that presents a capactive load is different from >>>>>>>>>>> a series capacitor: >>>>>>>>>>> >>>>>>>>>>> COB LEDs present capacitive loads through parasitic capacitances >>>>>>>>>>> inherent to their densely packed chip-on-board structure. These >>>>>>>>>>> capacitances arise between closely spaced LED dies, bonding >>>>>>>>>>> wires, and the substrate, affecting driver circuits during >>>>>>>>>>> switching. >>>>>>>>>> >>>>>>>>>> Since the current probe waveform is so different from the one that >>>>>>>>>> uses a resistor, one must be wrong, or likely both. >>>>>>>>>> >>>>>>>>>> Stray capacitances are at least six orders of magnitude from causing >>>>>>>>>> the phase shift that you are seeing. >>>>>>>>> >>>>>>>>> You're wrong, no doubt about it. Stray capacitance caused my problem. >>>>>>>>> And your sweeping generality at this juncture led me to question my >>>>>>>>> correct quantitative instincts. >>>>>>>>> >>>>>>>>> "ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>> voltage trace" leads to the correct solution. >>>>>>>>> >>>>>>>>> Hint: stray capacitance originates from more than one source. >>>>>>>> >>>>>>>> Probably the biggest capacitance is the LEDs themselves. >>>>>>> >>>>>>> Or the rectifier diodes. But still not much c. >>>>>>> >>>>>>> Measure it. >>>>>>>> >>>>>>>> If you used a sensible value current shunt resistor - ohms and not >>>>>>>> megohms - the effects of the capacitance would be invisible with 60 Hz >>>>>>>> excitation. >>>>>>>> >>>>>>>> Measure the capacitance and do the math. Or Spice it. >>>>>>>> >>>>>>>> "ELI the ICE man" is not quantitative. >>>>>> >>>>>> OK, We'll do it your quantitative way. Stray capacitance is at least six >>>>>> orders of magnitude higher than what you imagine. Because the biggest >>>>>> capacitance does not originate with the filament. >>>>>> >>>>>> There's no need to goof with a shunt resistor when an accurate current >>>>>> probe measurement is already available: >>>>>> >>>>>> <https://crcomp.net/ledfilament/curveprobe.png> >>>>>> >>>>>> It shows you everything you need to do your own math. Show me your >>>>>> math and I'll included on my webpage, with your permission. >>>> >>>> Iron-core current transformers get very nonlinear at low currents. The >>>> magnetic domains get sticky. You showed a gigantic CT. >>>> >>>>>> >>>>>> Hint for people who still don't see the light (so to speak): Bob Pease >>>>>> said, "My favorite programming language is solder." On a related note, >>>>>> Pease passionately hated one piece in particular, amid the equipment >>>>>> found in an electronic lab. >>>>>> >>>>>> Danke, >>>>>> >>>>>> -- >>>>>> 73, Don, WD7Q veritas _|_ >>>>>> liberabit | >>>>>> https://www.qsl.net/wd7q vos | >>>>>> >>>>> >>>>> This still doesn't make sense, but you piqued me enough to make >>>>> me do my own measurement. I don't see any phase shift between >>>>> voltage and current, although the power factor is certainly far >>>> >from unity. You can see my results here: >>>>> <https://cern.ch/jeroen/LEDstring>. >>>>> >>>>> Jeroen Belleman >>>> >>>> >>>> Was the curve on the left done at DC? >>> >>> No, it's the same data. I just plot I versus V. It's a bit >>> noisy; I should have filtered it a bit. >>> >>>> Why is your voltage waveform flat-topped? At 100 volts? >>>> >>>> At 30 mA, your 1K resistor drops 30 volts. So the "Voltage" connector >>>> doesn't represent the voltage seen by the DUT. >>> >>> True, the voltage recording is distorted by the superimposed current >>> curve. That also explains the flat top. I could use a smaller >>> current sense resistor, or compensate for its voltge drop. >> >> I don't understand the flat top. You are presumably scoping the 240 >> volt AC line. > >My AC source is not straight mains. I value my life. Instead, I used >a toy train variac transformer feeding a little 15VA mains transformer >in reverse. Plenty of opportunities to distort the waveform. Lots of people are afraid of electricity. Strange. > >> >>> >>>> >>>> And does the "Voltage" connector go straight into a scope channel? No >>>> probe? >>> >>> I used regular 1:10 scope probes. >>> >>>> Your current waveform does have about the right shape and timing. No >>>> time lags. >>>> >>>> The x-rayed COB seems to have a 4-diode bridge rectifier, two >>>> resistors, and one string of LEDs. That is more cost effective than >>>> having two strings, twice as many LEDs, each on half the time. >>> >>> True. I expected my strings to be similar to Don's, but they weren't. >>> >>>> John Larkin >>>> Highland Tech Glen Canyon Design Center >>>> Lunatic Fringe Electronics >>> >>> Exposing in some detail what I did lends people the ability to >>> really understand what's going on and to propose improvements. >>> Don's measurements leave too much room for mystery. >>> >>> Jeroen Belleman >>> >>> >> >> A 240-volt led lamp will be different from 120. It might have >> half-wave rectification. >> >> And I'd expect lots of different light bulbs. Some have electronics in >> the base. >> >> >> John Larkin >> Highland Tech Glen Canyon Design Center >> Lunatic Fringe Electronics > >The LED strings I tested do indeed conduct only one way. There are >some electronics in the base which I haven't yet looked at. > >Jeroen Belleman A 120 volt LED lamp can apparently work with just resistive current limiting. At 240, the economics is different, although one could just put a bunch of the 120 v COB things in series. I have a bulb here with no electronics and four COBs. It starts to light up around 80 volts. The COBs may be in series. What's interesting is the bulbs with a long twisty string of LEDs. How can they do that? https://www.amazon.com/Govee-Changing-Compatible-Assistant-Filament/dp/B0GF1J3YM7 John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-04-28 01:51 +1000 |
| Message-ID | <10so0mt$2fv30$1@dont-email.me> |
| In reply to | #743458 |
On 28/04/2026 1:11 am, john larkin wrote: > On Mon, 27 Apr 2026 10:59:20 +0200, Jeroen Belleman > <jeroen@nospam.please> wrote: > >> On 4/26/26 21:05, john larkin wrote: >>> On Sat, 25 Apr 2026 10:53:48 +0200, Jeroen Belleman >>> <jeroen@nospam.please> wrote: >>> >>>> On 4/25/26 00:42, john larkin wrote: >>>>> On Fri, 24 Apr 2026 22:23:32 +0200, Jeroen Belleman >>>>> <jeroen@nospam.please> wrote: >>>>> >>>>>> On 4/24/26 18:43, Don wrote: >>>>>>> john larkin wrote: >>>>>>>> john larkin wrote: >>>>>>>>> Don wrote: >>>>>>>>>> john larkin wrote: >>>>>>>>>>> Don wrote: >>>>>>>>>>>> john larkin wrote: >>>>>>>>>>>>> john larkin wrote: >>>>>>>>>>>>>> Don wrote: >>>>>>>>>>>>>>> Don wrote: >>>>>>>>>>>>>>>> Recent thread topic transitioned to a tentative opinion on a work-in- >>>>>>>>>>>>>>>> progress webpage: >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> <https://crcomp.net/ledfilament/index.php> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Radiography imparts interesting insight. Second opinions welcome! >>>>>>>>>>>>>>>> The current waveform flopped. Any advice on how to use a Fluke >>>>>>>>>>>>>>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >>>>>>>>>>>>>>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on >>>>>>>>>>>>>>>> the current probe? >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Alright you guys, a couple of current curve images are now available on >>>>>>>>>>>>>>> the webpage. For the present case, in regards to the probe's "P2 < P1" >>>>>>>>>>>>>>> orientation decal, P1 designates Line while P2 indicates Neutral. >>>>>>>>>>>>>>> The probe provides a sharper, cleaner curve compared to the >>>>>>>>>>>>>>> resistor. Both curves illustrate how the silicon filament primarily >>>>>>>>>>>>>>> presents itself as a capacitive load. >>>>>>>>>>>>>>> The filament's high voltage combined with its low amperage degrades >>>>>>>>>>>>>>> resistor curve quality. It took a 10 M ohm resistive current sensor for >>>>>>>>>>>>>>> the half-wave rectification effect to become visible. >>>>>>>>>>>>>>> The probe curve's mostly blue trace shows the peak-to-peak Line >>>>>>>>>>>>>>> voltage. It's used to properly trigger the scope. (Perhaps the scope's >>>>>>>>>>>>>>> line trigger accomplishes the same result with less effort?) The probe >>>>>>>>>>>>>>> curve's mostly green trace shows the current, with peaks and valleys >>>>>>>>>>>>>>> created by half-wave rectification at each end of the filament. >>>>>>>>>>>>>>> The current curve is set to 2mV per division. Does anyone know how >>>>>>>>>>>>>>> to transpose it to mA? >>>>>>>>>>>>>> >>>>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>>>> >>>>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Unless one of the thingies on the end is a cap. A DC curve would >>>>>>>>>>>>>> resolve that. >>>>>>>>>>>>>> >>>>>>>>>>>>>> A thermal image would be interesting too. >>>>>>>>>>>>>> >>>>>>>>>>>>> No, it lights up with DC, so there's no series cap. >>>>>>>>>>>> >>>>>>>>>>>> ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>>>>> voltage trace, so the filament must present a capacitive load. >>>>>>>>>>>> A silicon device that presents a capactive load is different from >>>>>>>>>>>> a series capacitor: >>>>>>>>>>>> >>>>>>>>>>>> COB LEDs present capacitive loads through parasitic capacitances >>>>>>>>>>>> inherent to their densely packed chip-on-board structure. These >>>>>>>>>>>> capacitances arise between closely spaced LED dies, bonding >>>>>>>>>>>> wires, and the substrate, affecting driver circuits during >>>>>>>>>>>> switching. >>>>>>>>>>> >>>>>>>>>>> Since the current probe waveform is so different from the one that >>>>>>>>>>> uses a resistor, one must be wrong, or likely both. >>>>>>>>>>> >>>>>>>>>>> Stray capacitances are at least six orders of magnitude from causing >>>>>>>>>>> the phase shift that you are seeing. >>>>>>>>>> >>>>>>>>>> You're wrong, no doubt about it. Stray capacitance caused my problem. >>>>>>>>>> And your sweeping generality at this juncture led me to question my >>>>>>>>>> correct quantitative instincts. >>>>>>>>>> >>>>>>>>>> "ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>>> voltage trace" leads to the correct solution. >>>>>>>>>> >>>>>>>>>> Hint: stray capacitance originates from more than one source. >>>>>>>>> >>>>>>>>> Probably the biggest capacitance is the LEDs themselves. >>>>>>>> >>>>>>>> Or the rectifier diodes. But still not much c. >>>>>>>> >>>>>>>> Measure it. >>>>>>>>> >>>>>>>>> If you used a sensible value current shunt resistor - ohms and not >>>>>>>>> megohms - the effects of the capacitance would be invisible with 60 Hz >>>>>>>>> excitation. >>>>>>>>> >>>>>>>>> Measure the capacitance and do the math. Or Spice it. >>>>>>>>> >>>>>>>>> "ELI the ICE man" is not quantitative. >>>>>>> >>>>>>> OK, We'll do it your quantitative way. Stray capacitance is at least six >>>>>>> orders of magnitude higher than what you imagine. Because the biggest >>>>>>> capacitance does not originate with the filament. >>>>>>> >>>>>>> There's no need to goof with a shunt resistor when an accurate current >>>>>>> probe measurement is already available: >>>>>>> >>>>>>> <https://crcomp.net/ledfilament/curveprobe.png> >>>>>>> >>>>>>> It shows you everything you need to do your own math. Show me your >>>>>>> math and I'll included on my webpage, with your permission. >>>>> >>>>> Iron-core current transformers get very nonlinear at low currents. The >>>>> magnetic domains get sticky. You showed a gigantic CT. >>>>> >>>>>>> >>>>>>> Hint for people who still don't see the light (so to speak): Bob Pease >>>>>>> said, "My favorite programming language is solder." On a related note, >>>>>>> Pease passionately hated one piece in particular, amid the equipment >>>>>>> found in an electronic lab. >>>>>>> >>>>>>> Danke, >>>>>>> >>>>>>> -- >>>>>>> 73, Don, WD7Q veritas _|_ >>>>>>> liberabit | >>>>>>> https://www.qsl.net/wd7q vos | >>>>>>> >>>>>> >>>>>> This still doesn't make sense, but you piqued me enough to make >>>>>> me do my own measurement. I don't see any phase shift between >>>>>> voltage and current, although the power factor is certainly far >>>>> >from unity. You can see my results here: >>>>>> <https://cern.ch/jeroen/LEDstring>. >>>>>> >>>>>> Jeroen Belleman >>>>> >>>>> >>>>> Was the curve on the left done at DC? >>>> >>>> No, it's the same data. I just plot I versus V. It's a bit >>>> noisy; I should have filtered it a bit. >>>> >>>>> Why is your voltage waveform flat-topped? At 100 volts? >>>>> >>>>> At 30 mA, your 1K resistor drops 30 volts. So the "Voltage" connector >>>>> doesn't represent the voltage seen by the DUT. >>>> >>>> True, the voltage recording is distorted by the superimposed current >>>> curve. That also explains the flat top. I could use a smaller >>>> current sense resistor, or compensate for its voltge drop. >>> >>> I don't understand the flat top. You are presumably scoping the 240 >>> volt AC line. >> >> My AC source is not straight mains. I value my life. Instead, I used >> a toy train variac transformer feeding a little 15VA mains transformer >> in reverse. Plenty of opportunities to distort the waveform. > > Lots of people are afraid of electricity. Strange. > > >> >>> >>>> >>>>> >>>>> And does the "Voltage" connector go straight into a scope channel? No >>>>> probe? >>>> >>>> I used regular 1:10 scope probes. >>>> >>>>> Your current waveform does have about the right shape and timing. No >>>>> time lags. >>>>> >>>>> The x-rayed COB seems to have a 4-diode bridge rectifier, two >>>>> resistors, and one string of LEDs. That is more cost effective than >>>>> having two strings, twice as many LEDs, each on half the time. >>>> >>>> True. I expected my strings to be similar to Don's, but they weren't. >>>> >>>>> Highland Tech Glen Canyon Design Center >>>>> Lunatic Fringe Electronics >>>> >>>> Exposing in some detail what I did lends people the ability to >>>> really understand what's going on and to propose improvements. >>>> Don's measurements leave too much room for mystery. >>> A 240-volt led lamp will be different from 120. It might have >>> half-wave rectification. >>> >>> And I'd expect lots of different light bulbs. Some have electronics in >>> the base. >> >>> Highland Tech Glen Canyon Design Center >>> Lunatic Fringe Electronics >> >> The LED strings I tested do indeed conduct only one way. There are >> some electronics in the base which I haven't yet looked at. > > A 120 volt LED lamp can apparently work with just resistive current > limiting. At 240, the economics is different, although one could just > put a bunch of the 120 v COB things in series. The economic aren't going to be wildly different. It's going to pay off to put in twice as many LEDs. LED lamps dissipate a whol;e lot less power than their tungsten filament predecessors so the extra power dissippation isn't gong to be a problem, but it may make sense to go in for smaller LEDS. It's not an elegant solution - some sort of reactive current current switching with fast current switches could give the same amount of light with half the power dissipation, but it going to take more expensive components, if fewer of them. > I have a bulb here with no electronics and four COBs. It starts to > light up around 80 volts. The COBs may be in series. Who knows. > What's interesting is the bulbs with a long twisty string of LEDs. How > can they do that? > > https://www.amazon.com/Govee-Changing-Compatible-Assistant-Filament/dp/B0GF1J3YM7 We all know about flexible printed circuits. The image suggests that there might be bits of rigid support for the strips of flexible material that carry the LEDs and their connecting conductor. It's an exercise in visual design rather than any kind of serious engineering. A real lunatic might put LEDs onto strips of glass and rely on transparent tin oxide for the conductor. https://en.wikipedia.org/wiki/Transparent_conducting_film -- Bill Sloman, Sydney -- Bill Sloman, Sydney
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| From | Jeroen Belleman <jeroen@nospam.please> |
|---|---|
| Date | 2026-04-27 21:40 +0200 |
| Message-ID | <10soe2o$2kghi$1@dont-email.me> |
| In reply to | #743458 |
On 4/27/26 17:11, john larkin wrote: > On Mon, 27 Apr 2026 10:59:20 +0200, Jeroen Belleman > <jeroen@nospam.please> wrote: > >> On 4/26/26 21:05, john larkin wrote: >>> On Sat, 25 Apr 2026 10:53:48 +0200, Jeroen Belleman >>> <jeroen@nospam.please> wrote: >>> >>>> On 4/25/26 00:42, john larkin wrote: >>>>> On Fri, 24 Apr 2026 22:23:32 +0200, Jeroen Belleman >>>>> <jeroen@nospam.please> wrote: >>>>> >>>>>> On 4/24/26 18:43, Don wrote: >>>>>>> john larkin wrote: >>>>>>>> john larkin wrote: >>>>>>>>> Don wrote: >>>>>>>>>> john larkin wrote: >>>>>>>>>>> Don wrote: >>>>>>>>>>>> john larkin wrote: >>>>>>>>>>>>> john larkin wrote: >>>>>>>>>>>>>> Don wrote: >>>>>>>>>>>>>>> Don wrote: >>>>>>>>>>>>>>>> Recent thread topic transitioned to a tentative opinion on a work-in- >>>>>>>>>>>>>>>> progress webpage: >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> <https://crcomp.net/ledfilament/index.php> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Radiography imparts interesting insight. Second opinions welcome! >>>>>>>>>>>>>>>> The current waveform flopped. Any advice on how to use a Fluke >>>>>>>>>>>>>>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >>>>>>>>>>>>>>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on >>>>>>>>>>>>>>>> the current probe? >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Alright you guys, a couple of current curve images are now available on >>>>>>>>>>>>>>> the webpage. For the present case, in regards to the probe's "P2 < P1" >>>>>>>>>>>>>>> orientation decal, P1 designates Line while P2 indicates Neutral. >>>>>>>>>>>>>>> The probe provides a sharper, cleaner curve compared to the >>>>>>>>>>>>>>> resistor. Both curves illustrate how the silicon filament primarily >>>>>>>>>>>>>>> presents itself as a capacitive load. >>>>>>>>>>>>>>> The filament's high voltage combined with its low amperage degrades >>>>>>>>>>>>>>> resistor curve quality. It took a 10 M ohm resistive current sensor for >>>>>>>>>>>>>>> the half-wave rectification effect to become visible. >>>>>>>>>>>>>>> The probe curve's mostly blue trace shows the peak-to-peak Line >>>>>>>>>>>>>>> voltage. It's used to properly trigger the scope. (Perhaps the scope's >>>>>>>>>>>>>>> line trigger accomplishes the same result with less effort?) The probe >>>>>>>>>>>>>>> curve's mostly green trace shows the current, with peaks and valleys >>>>>>>>>>>>>>> created by half-wave rectification at each end of the filament. >>>>>>>>>>>>>>> The current curve is set to 2mV per division. Does anyone know how >>>>>>>>>>>>>>> to transpose it to mA? >>>>>>>>>>>>>> >>>>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>>>> >>>>>>>>>>>>>> It can't be capacitive. It has no mechanism to store energy. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Unless one of the thingies on the end is a cap. A DC curve would >>>>>>>>>>>>>> resolve that. >>>>>>>>>>>>>> >>>>>>>>>>>>>> A thermal image would be interesting too. >>>>>>>>>>>>>> >>>>>>>>>>>>> No, it lights up with DC, so there's no series cap. >>>>>>>>>>>> >>>>>>>>>>>> ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>>>>> voltage trace, so the filament must present a capacitive load. >>>>>>>>>>>> A silicon device that presents a capactive load is different from >>>>>>>>>>>> a series capacitor: >>>>>>>>>>>> >>>>>>>>>>>> COB LEDs present capacitive loads through parasitic capacitances >>>>>>>>>>>> inherent to their densely packed chip-on-board structure. These >>>>>>>>>>>> capacitances arise between closely spaced LED dies, bonding >>>>>>>>>>>> wires, and the substrate, affecting driver circuits during >>>>>>>>>>>> switching. >>>>>>>>>>> >>>>>>>>>>> Since the current probe waveform is so different from the one that >>>>>>>>>>> uses a resistor, one must be wrong, or likely both. >>>>>>>>>>> >>>>>>>>>>> Stray capacitances are at least six orders of magnitude from causing >>>>>>>>>>> the phase shift that you are seeing. >>>>>>>>>> >>>>>>>>>> You're wrong, no doubt about it. Stray capacitance caused my problem. >>>>>>>>>> And your sweeping generality at this juncture led me to question my >>>>>>>>>> correct quantitative instincts. >>>>>>>>>> >>>>>>>>>> "ELI the ICE man. The trace of the current curve clearly leads the >>>>>>>>>> voltage trace" leads to the correct solution. >>>>>>>>>> >>>>>>>>>> Hint: stray capacitance originates from more than one source. >>>>>>>>> >>>>>>>>> Probably the biggest capacitance is the LEDs themselves. >>>>>>>> >>>>>>>> Or the rectifier diodes. But still not much c. >>>>>>>> >>>>>>>> Measure it. >>>>>>>>> >>>>>>>>> If you used a sensible value current shunt resistor - ohms and not >>>>>>>>> megohms - the effects of the capacitance would be invisible with 60 Hz >>>>>>>>> excitation. >>>>>>>>> >>>>>>>>> Measure the capacitance and do the math. Or Spice it. >>>>>>>>> >>>>>>>>> "ELI the ICE man" is not quantitative. >>>>>>> >>>>>>> OK, We'll do it your quantitative way. Stray capacitance is at least six >>>>>>> orders of magnitude higher than what you imagine. Because the biggest >>>>>>> capacitance does not originate with the filament. >>>>>>> >>>>>>> There's no need to goof with a shunt resistor when an accurate current >>>>>>> probe measurement is already available: >>>>>>> >>>>>>> <https://crcomp.net/ledfilament/curveprobe.png> >>>>>>> >>>>>>> It shows you everything you need to do your own math. Show me your >>>>>>> math and I'll included on my webpage, with your permission. >>>>> >>>>> Iron-core current transformers get very nonlinear at low currents. The >>>>> magnetic domains get sticky. You showed a gigantic CT. >>>>> >>>>>>> >>>>>>> Hint for people who still don't see the light (so to speak): Bob Pease >>>>>>> said, "My favorite programming language is solder." On a related note, >>>>>>> Pease passionately hated one piece in particular, amid the equipment >>>>>>> found in an electronic lab. >>>>>>> >>>>>>> Danke, >>>>>>> >>>>>>> -- >>>>>>> 73, Don, WD7Q veritas _|_ >>>>>>> liberabit | >>>>>>> https://www.qsl.net/wd7q vos | >>>>>>> >>>>>> >>>>>> This still doesn't make sense, but you piqued me enough to make >>>>>> me do my own measurement. I don't see any phase shift between >>>>>> voltage and current, although the power factor is certainly far >>>>> >from unity. You can see my results here: >>>>>> <https://cern.ch/jeroen/LEDstring>. >>>>>> >>>>>> Jeroen Belleman >>>>> >>>>> >>>>> Was the curve on the left done at DC? >>>> >>>> No, it's the same data. I just plot I versus V. It's a bit >>>> noisy; I should have filtered it a bit. >>>> >>>>> Why is your voltage waveform flat-topped? At 100 volts? >>>>> >>>>> At 30 mA, your 1K resistor drops 30 volts. So the "Voltage" connector >>>>> doesn't represent the voltage seen by the DUT. >>>> >>>> True, the voltage recording is distorted by the superimposed current >>>> curve. That also explains the flat top. I could use a smaller >>>> current sense resistor, or compensate for its voltge drop. >>> >>> I don't understand the flat top. You are presumably scoping the 240 >>> volt AC line. >> >> My AC source is not straight mains. I value my life. Instead, I used >> a toy train variac transformer feeding a little 15VA mains transformer >> in reverse. Plenty of opportunities to distort the waveform. > > Lots of people are afraid of electricity. Strange. I'm not afraid, but I'm not stupid either. 240V straight from the mains can kill. For sure it bites. > > >> >>> >>>> >>>>> >>>>> And does the "Voltage" connector go straight into a scope channel? No >>>>> probe? >>>> >>>> I used regular 1:10 scope probes. >>>> >>>>> Your current waveform does have about the right shape and timing. No >>>>> time lags. >>>>> >>>>> The x-rayed COB seems to have a 4-diode bridge rectifier, two >>>>> resistors, and one string of LEDs. That is more cost effective than >>>>> having two strings, twice as many LEDs, each on half the time. >>>> >>>> True. I expected my strings to be similar to Don's, but they weren't. >>>> >>>>> John Larkin >>>>> Highland Tech Glen Canyon Design Center >>>>> Lunatic Fringe Electronics >>>> >>>> Exposing in some detail what I did lends people the ability to >>>> really understand what's going on and to propose improvements. >>>> Don's measurements leave too much room for mystery. >>>> >>>> Jeroen Belleman >>>> >>>> >>> >>> A 240-volt led lamp will be different from 120. It might have >>> half-wave rectification. >>> >>> And I'd expect lots of different light bulbs. Some have electronics in >>> the base. >>> >>> >>> John Larkin >>> Highland Tech Glen Canyon Design Center >>> Lunatic Fringe Electronics >> >> The LED strings I tested do indeed conduct only one way. There are >> some electronics in the base which I haven't yet looked at. >> >> Jeroen Belleman > > A 120 volt LED lamp can apparently work with just resistive current > limiting. At 240, the economics is different, although one could just > put a bunch of the 120 v COB things in series. That's what they did. There were two series pairs. The PCB in the base has a full-wave rectifier, an MT7606 LED driver and a bunch of resistors. I didn't reverse-engineer it; the copper traces are hidden under a thick layer of white laquer, but I can sort-of guess how it's done. I'd expect a roughly constant amount of light for a wide range of voltage. I didn't try that. > > I have a bulb here with no electronics and four COBs. It starts to > light up around 80 volts. The COBs may be in series. > > What's interesting is the bulbs with a long twisty string of LEDs. How > can they do that? > > https://www.amazon.com/Govee-Changing-Compatible-Assistant-Filament/dp/B0GF1J3YM7 > > > John Larkin > Highland Tech Glen Canyon Design Center > Lunatic Fringe Electronics Jeroen Belleman
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| From | JM <sunaecoNoChoppedPork@gmail.com> |
|---|---|
| Date | 2026-04-22 16:36 +0100 |
| Message-ID | <2mqhuk9stmli0ql43nkg8tl62r14cj2eq3@4ax.com> |
| In reply to | #743194 |
On Tue, 21 Apr 2026 14:39:14 -0000 (UTC), "Don" <g@crcomp.net> wrote: >Don wrote: >> Recent thread topic transitioned to a tentative opinion on a work-in- >> progress webpage: >> >> <https://crcomp.net/ledfilament/index.php> >> >> Radiography imparts interesting insight. Second opinions welcome! >> The current waveform flopped. Any advice on how to use a Fluke >> 80i-1000s connected to a Tek 2465B to display the 120 VAC current >> wave is appreciated in advance. Also, what does "P2 < P1" signify on >> the current probe? > >Alright you guys, a couple of current curve images are now available on >the webpage. For the present case, in regards to the probe's "P2 < P1" >orientation decal, P1 designates Line while P2 indicates Neutral. > The probe provides a sharper, cleaner curve compared to the >resistor. Both curves illustrate how the silicon filament primarily >presents itself as a capacitive load. > The filament's high voltage combined with its low amperage degrades >resistor curve quality. It took a 10 M ohm resistive current sensor for >the half-wave rectification effect to become visible. > The probe curve's mostly blue trace shows the peak-to-peak Line >voltage. It's used to properly trigger the scope. (Perhaps the scope's >line trigger accomplishes the same result with less effort?) The probe >curve's mostly green trace shows the current, with peaks and valleys >created by half-wave rectification at each end of the filament. > The current curve is set to 2mV per division. Does anyone know how >to transpose it to mA? > >Danke, You're faffing about. Make a cup of tea, sit down and think for a minute.
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| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-04-22 17:10 +0000 |
| Message-ID | <20260422a@crcomp.net> |
| In reply to | #743234 |
JM wrote:
> Don wrote:
>>Don wrote:
>>> Recent thread topic transitioned to a tentative opinion on a work-in-
>>> progress webpage:
>>>
>>> <https://crcomp.net/ledfilament/index.php>
>>>
>>> Radiography imparts interesting insight. Second opinions welcome!
>>> The current waveform flopped. Any advice on how to use a Fluke
>>> 80i-1000s connected to a Tek 2465B to display the 120 VAC current
>>> wave is appreciated in advance. Also, what does "P2 < P1" signify on
>>> the current probe?
>>
>>Alright you guys, a couple of current curve images are now available on
>>the webpage. For the present case, in regards to the probe's "P2 < P1"
>>orientation decal, P1 designates Line while P2 indicates Neutral.
>> The probe provides a sharper, cleaner curve compared to the
>>resistor. Both curves illustrate how the silicon filament primarily
>>presents itself as a capacitive load.
>> The filament's high voltage combined with its low amperage degrades
>>resistor curve quality. It took a 10 M ohm resistive current sensor for
>>the half-wave rectification effect to become visible.
>> The probe curve's mostly blue trace shows the peak-to-peak Line
>>voltage. It's used to properly trigger the scope. (Perhaps the scope's
>>line trigger accomplishes the same result with less effort?) The probe
>>curve's mostly green trace shows the current, with peaks and valleys
>>created by half-wave rectification at each end of the filament.
>> The current curve is set to 2mV per division. Does anyone know how
>>to transpose it to mA?
>
> You're faffing about. Make a cup of tea, sit down and think for a
> minute.
What does a forking fantasy about faffing have to do with your bright
idea to use a series resistor to create a current curve? 1, 10, 100,
10K, 100K, 1M series resistors all show slightly attenuated 320 VAC.
What do you think about that?
Danke,
--
73, Don, WD7Q veritas _|_
liberabit |
https://www.qsl.net/wd7q vos |
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| From | JM <sunaecoNoChoppedPork@gmail.com> |
|---|---|
| Date | 2026-04-22 18:17 +0100 |
| Message-ID | <bh0iuk984fsvk1tb6gbkl64vjidatr7rf8@4ax.com> |
| In reply to | #743242 |
On Wed, 22 Apr 2026 17:10:51 -0000 (UTC), "Don" <g@crcomp.net> wrote: >What does a forking fantasy about faffing have to do with your bright >idea to use a series resistor to create a current curve? 1, 10, 100, >10K, 100K, 1M series resistors all show slightly attenuated 320 VAC. >What do you think about that? So you think you see 320V ac across a 1 ohm resistor. Think about it.
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