Re: CoB LED filament analysis

From	john larkin <jl@glen--canyon.com>
Newsgroups	sci.electronics.design
Subject	Re: CoB LED filament analysis
Date	2026-04-26 10:17 -0700
Organization	A noiseless patient Spider
Message-ID	<0mhsukhtmsbbd9t4hpt7rb84ushftnfk7f@4ax.com> (permalink)
References	(10 earlier) <20260425c@crcomp.net> <10skrd7$1fnd2$1@dont-email.me> <20260426a@crcomp.net> <20260426b@crcomp.net> <20260426c@crcomp.net>

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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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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 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

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