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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 |
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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 3 of 6 — ← Prev page 1 2 [3] 4 5 6 Next page →
| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-04-24 08:04 -0700 |
| Message-ID | <rh1nukhsan6d1hkhamqvl6bqr46jv1cj11@4ax.com> |
| In reply to | #743304 |
On Fri, 24 Apr 2026 07:55:34 -0700, john larkin <jl@glen--canyon.com> wrote: >On Fri, 24 Apr 2026 13:37:43 -0000 (UTC), "Don" <g@crcomp.net> 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. >>>>>> >>>>>>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. >> >>Danke, > >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. > > > >John Larkin >Highland Tech Glen Canyon Design Center >Lunatic Fringe Electronics John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
[toc] | [prev] | [next] | [standalone]
| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-04-24 16:43 +0000 |
| Message-ID | <20260424b@crcomp.net> |
| In reply to | #743306 |
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 |
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| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-04-24 20:15 +0000 |
| Message-ID | <20260424d@crcomp.net> |
| In reply to | #743312 |
Don wrote:
<snip>
> 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.
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.
2. Filaments behave better when you use a brand new bulb in place of a
filament from a broken bulb.
3. Don't conjure up spirits resting in peace.
The webpage will be updated with: corrected images of the current curve,
photos of a new bulb without a breadboard, an internal schematic of the
CoB LED, piglet's diagram, and a lab report.
Calculating the capacitance from the original current curve with a
breadboard in situ would be fun. But the stray capacitance detour won't
be mentioned on the webpage to keep things simple.
This has been an entertaining side-show for me. I hope you guys had fun
too. It beats doom-scrolling.
Danke,
--
73, Don, WD7Q veritas _|_
liberabit |
https://www.qsl.net/wd7q vos |
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-04-26 03:45 +1000 |
| Message-ID | <10siukh$10lh9$1@dont-email.me> |
| In reply to | #743331 |
On 25/04/2026 6:15 am, Don wrote: > Don wrote: <snip> >> 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. > > 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. Not if they are used sensibly. How you managed to screw up your circuit by building it on a solderless bread-broad is anybody's guess. Not that I'd ever use one. You do have to know what you are connecting to what, and anything that hides the connections or can introduce an unexpected connection that you can't see has got to be a bad idea. > 2. Filaments behave better when you use a brand new bulb in place of a > filament from a broken bulb. Strictly speaking, a filament is something long and thin. The fact that the little bits of circuit boards with added light-emitting diodes get plugged into lamps originally designed around tungsten filament lamps doesn't make them "filaments" > 3. Don't conjure up spirits resting in peace. Remembering Bob Pease isn't conjuring him up. > The webpage will be updated with: corrected images of the current curve, > photos of a new bulb without a breadboard, an internal schematic of the > CoB LED, piglet's diagram, and a lab report. > > Calculating the capacitance from the original current curve with a > breadboard in situ would be fun. But the stray capacitance detour won't > be mentioned on the webpage to keep things simple. > > This has been an entertaining side-show for me. I hope you guys had fun > too. It beats doom-scrolling. It has been a diabolical exhibition of confused thinking. If you find that entertaining, your attitudes need work. Piglet and John May did eventually introduce some sanity, but it took quite a while. There's probably a respectable circuit to do the job, but wasting energy in current limiting resistors won't be part of it. You probably need a rectifier with power factor correction to set up a more or less steady DC voltage across a capacitor and a switching driver to turn that into a well-controlled more or less constant current through a string of illumination LEDs. There do seem to be some fast GaN switches around that could run at few MHz, and control a switched current though a nickel-zinc cored inductor. Ideally you'd want a printed winding, so an EFD core or the like. I've yet to see anything like it. I replaced the flat dome ceiling lamps (there were four of them) in my flat a few years ago with LED-based units, but just bought four of them and paid an electrician to put them up - drilling the necessary mounting holes in a reinforced concrete ceiling needs more strength than I've now got. It took ages when I was younger. The lamps weren't designed to be dismantled and I didn't try. The LEDs do seem to be well-spread out - the surface brightness is pretty uniform. I'd fooled around with LED replacements for the linear quartz halogen lamps in the originals, but none of them proved remotely reliable, losing output rapidly over a few months as individual LEDs conked out. The new lamps don't seem to be losing brightness. -- Bill Sloman, Sydney
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-04-25 11:14 -0700 |
| Message-ID | <hs0quktdbcqrgshrkoejdgbfaesdarcvqj@4ax.com> |
| In reply to | #743331 |
On Fri, 24 Apr 2026 20:15:46 -0000 (UTC), "Don" <g@crcomp.net> wrote: >Don wrote: > ><snip> > >> 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. > >Game over. Lessons learned: > >1. Pease hated solderless breadboards for a good reason: they introduce > stray capacitance. 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 John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-04-25 22:56 +0000 |
| Message-ID | <20260425a@crcomp.net> |
| In reply to | #743368 |
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,
--
73, Don, WD7Q veritas _|_
liberabit |
https://www.qsl.net/wd7q vos |
[toc] | [prev] | [next] | [standalone]
| From | ehsjr <ehsjr@verizon.net> |
|---|---|
| Date | 2026-04-25 21:33 -0400 |
| Message-ID | <10sjq27$1589n$1@ehsjr.eternal-september.org> |
| In reply to | #743381 |
On 4/25/2026 6:56 PM, 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. > 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. How about parallel and/or series R? Gunk between breadboard contacts or oxidized/loose contacts? Ed > > 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, > > -- > 73, Don, WD7Q veritas _|_ > liberabit | > https://www.qsl.net/wd7q vos | >
[toc] | [prev] | [next] | [standalone]
| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-04-26 02:18 +0000 |
| Message-ID | <20260425b@crcomp.net> |
| In reply to | #743385 |
ehsjr <ehsjr@verizon.net> wrote:
> On 4/25/2026 6:56 PM, 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.
>> 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.
>
> How about parallel and/or series R? Gunk between breadboard contacts
> or oxidized/loose contacts?
Yes! All of the above plausibly contribute to capacitive current curve
corruption caused by my real world breadboard /system/, so to speak.
You get it. It's critical to understand the difference between the
idealized stray capacitance of 2, 3, or 5 pF, as mentioned in
TROUBLSHOOTING ANALOG CIRCUITS by Pease and my breadboard system's
real world stray capacitance.
Although idealized components make theory easier to comprehend, it
can be a mistake to assume idealized values in the real world. With this
very project, for instance.
Danke,
--
73, Don, WD7Q veritas _|_
liberabit |
https://www.qsl.net/wd7q vos |
[toc] | [prev] | [next] | [standalone]
| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-04-25 20:08 -0700 |
| Message-ID | <o80rukd3nsquo4gtu5aqk4e2tfaf5fp0n3@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. 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? >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, John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
[toc] | [prev] | [next] | [standalone]
| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-04-26 04:44 +0000 |
| Message-ID | <20260425c@crcomp.net> |
| In reply to | #743387 |
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.
Danke,
--
73, Don, WD7Q veritas _|_
liberabit |
https://www.qsl.net/wd7q vos |
[toc] | [prev] | [next] | [standalone]
| From | Arie de Muijnck <noreply@ademu.nl> |
|---|---|
| Date | 2026-04-26 13:03 +0200 |
| Message-ID | <10skrd7$1fnd2$1@dont-email.me> |
| In reply to | #743389 |
On 2026-04-26 06:44, 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. > > Danke, > > -- > 73, Don, WD7Q veritas _|_ > liberabit | > https://www.qsl.net/wd7q vos | > 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. Arie
[toc] | [prev] | [next] | [standalone]
| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-04-26 11:35 +0000 |
| Message-ID | <20260426a@crcomp.net> |
| In reply to | #743401 |
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.
Danke,
--
73, Don, WD7Q veritas _|_
liberabit |
https://www.qsl.net/wd7q vos |
[toc] | [prev] | [next] | [standalone]
| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-04-26 11:43 +0000 |
| Message-ID | <20260426b@crcomp.net> |
| In reply to | #743406 |
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 |
[toc] | [prev] | [next] | [standalone]
| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-04-26 16:44 +0000 |
| Message-ID | <20260426c@crcomp.net> |
| In reply to | #743407 |
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 |
[toc] | [prev] | [next] | [standalone]
| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-04-26 10:17 -0700 |
| Message-ID | <0mhsukhtmsbbd9t4hpt7rb84ushftnfk7f@4ax.com> |
| In reply to | #743416 |
On Sun, 26 Apr 2026 16:44:55 -0000 (UTC), "Don" <g@crcomp.net> 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. > Looks to me that the four diodes make a full-wave bridge, driving a single series string of LEDs, with two series resistors. A CT without a burden resistor becomes a differentiator. Big cheap iron-core CTs are very nonlinear at low currents anyhow. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Arie de Muijnck <noreply@ademu.nl> |
|---|---|
| Date | 2026-04-26 19:58 +0200 |
| Message-ID | <10sljo0$1fnd2$2@dont-email.me> |
| In reply to | #743416 |
On 2026-04-26 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. 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. Arie > > 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 | >
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| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-04-26 19:22 +0000 |
| Message-ID | <20260426e@crcomp.net> |
| In reply to | #743424 |
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.
Thank you for your kind, thoughtful followup, Arie. AI adds additional
food for thought:
There is no publicly available comprehensive teardown video
or detailed technical internal diagram specifically for the
Fluke i1000s AC current probe. Because the device is a
ruggedized, safety-rated tool designed for industrial
environments, it is typically serviced as a sealed unit
rather than opened by users.
### Internal Architecture Overview
While a detailed schematic is not publicly provided, the
mechanical and electrical construction follows the standard
design for a high-quality, passive clamp-on current
transformer.
* **Split-Core Transformer:** The "jaws" of the clamp
contain a laminated magnetic core assembly that pivots. When
closed around a conductor, this core forms a closed loop,
concentrating the magnetic flux induced by the AC current
in the conductor
* **Secondary Winding:** Wrapped around this core is a
secondary coil with a high number of turns. This coil converts
the primary current into a proportional, lower-level current
signal.
* **Passive Signal Conditioning:** Inside the probe's handle,
the secondary signal passes through a network of resistors
and potentially capacitors. This passive network provides the
selectable output ranges (1 mV/A to 100 mV/A) and includes
filtering components to minimize high-frequency noise and
ringing, which is crucial for accurately capturing distorted
waveforms on an oscilloscope.
* **Shielding and Construction:** The internal circuitry is
housed within a flame-retardant, high-impact plastic enclosure.
The output is fed through a high-quality coaxial cable, which
is shielded to prevent external electromagnetic interference
(EMI) from corrupting the low-level signal before it reaches
the measurement instrument.
It will take me a while to digest it. Here's an excerpt from Fluke's
user manual:
Operation
Use the following procedure to make a measurement:
1. Connect the i1000s Current Probe to the desired input channel on the
oscilloscope.
2. On the Current Probe, select the least sensitive range (1 mV/A). See
Figure 1 for selector switch location.
3. On your oscilloscope, select an appropriate range. Use a 1:1 probe
setting.
4. Clamp the probe around the conductor to be measured, and observe the
current waveform on your oscilloscope display.
5. Calculate the Amps-per-division on your oscilloscope by dividing
the vertical scale (mV or V per division) by the i1000s switch position
(1, 10, or 100 mV/A). For example:
20 mV per division = 20 A per division 1 mV/A
<https://assets.fluke.com/manuals/i1000s__umeng0100.pdf>
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:
不诱于誉，不恐于诽，率道而行，端然正己。
Not tempted by praise, not intimidated by criticism; walking the path
of principle, one remains upright and true to oneself.
Danke,
--
73, Don, WD7Q veritas _|_
liberabit |
https://www.qsl.net/wd7q vos |
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| From | "Don" <g@crcomp.net> |
|---|---|
| Date | 2026-05-19 03:30 +0000 |
| Message-ID | <20260518a@crcomp.net> |
| In reply to | #743433 |
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:
>
> 不诱于誉，不恐于诽，率道而行，端然正己。
>
> 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 |
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-05-19 08:26 -0700 |
| Message-ID | <q00p0l9vojr53j07301p9u6oa6vm5gnlrh@4ax.com> |
| In reply to | #744082 |
On Tue, 19 May 2026 03:30:13 -0000 (UTC), "Don" <g@crcomp.net> 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, A cheap iron-core current transformer will behave very badly at low current. You are trying to measure mA with a 1000A CT. Parts per million. Instrument it better. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Arie de Muijnck <noreply@ademu.nl> |
|---|---|
| Date | 2026-05-19 18:23 +0200 |
| Message-ID | <10ui2q5$2nnv0$1@dont-email.me> |
| In reply to | #744082 |
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: >> >> 不诱于誉，不恐于诽，率道而行，端然正己。 >> >> 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
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