Re: CoB LED filament analysis

From	john larkin <jl@glen--canyon.com>
Newsgroups	sci.electronics.design
Subject	Re: CoB LED filament analysis
Date	2026-04-24 15:19 -0700
Organization	Highland Technology
Message-ID	<0ponuk58f6uj0iiiutb9qv42vbnkabdf6c@4ax.com> (permalink)
References	(9 earlier) <20260423b@crcomp.net> <20260423c@crcomp.net> <10sg8na$3jsof$4@dont-email.me> <clanukdpoefq7tup8n7arejj6va18biab5@4ax.com> <10sgkeb$3jsof$6@dont-email.me>

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On Fri, 24 Apr 2026 21:39:39 +0100, John R Walliker
<jrwalliker@gmail.com> wrote:

>On 24/04/2026 18:39, john larkin wrote:
>> On Fri, 24 Apr 2026 18:19:38 +0100, John R Walliker
>> <jrwalliker@gmail.com> wrote:
>> 
>>> On 24/04/2026 03:53, Don wrote:
>>>> Don <g@crcomp.net> wrote:
>>>>> Don wrote:
>>>>>
>>>>> <snip>
>>>>>
>>>>>> It's time for a brain teaser to
>>>>>> get things back on track. Put on your quantitative instincts hat and
>>>>>> take a good long look at all of the images shown at:
>>>>>>
>>>>>> <https://crcomp.net/ledfilament/index.php>
>>>>>>
>>>>>> Now put on your thinking cap. There's something glaringly wrong (so to
>>>>>> speak) with the experiment. It may explain the phase difference
>>>>>> discrepancy. Stay tuned.
>>>>>
>>>>> Alright you guys, this thread's fun again! There's yet another
>>>>> intuitively obvious source of error for those with quantitative
>>>>> instinctive eyes to see. And it has nothing whatsoever to do with my
>>>>> 320 VACp-p typo.  Hint: imagine how my empirical current curves could
>>>>> be correct.
>>>
>>> The LED string does not begin to conduct until the peak voltage has
>>> been reached.  Then the current increases abruptly and the voltage
>>> collapses due to a relatively high source impedance.  The string
>>> continues to conduct even as the voltage is collapsing.  The
>>> voltage collapse is not immediate because there is a significant
>>> capacitance across the LED string after the source resistance
>>> (which may be the current sense resistor).
>>>
>>> John
>> 
>> Umm, no.
>
>OK then.  What is wrong with my interpretation?
>There is a sudden drop in the voltage waveform
>which implies a sudden increase in the current drawn.
>The current waveform confirms this.  The slope in the
>voltage waveform suggests a capacitive component.
>There must be some hysteresis, which is the most
>puzzling element.
>
>
>
>> John Larkin
>> Highland Tech Glen Canyon Design Center
>> Lunatic Fringe Electronics

With 60 Hz excitation, there will be no time lags. Nothing will be
sudden.

Instantaneous current will be about

   I = (Vline-Vleds) / R

where R is the sum of the two end resistances. No time factor, no
hysteresis.

This needs a proper measurement. DC with a DVM would be best, since
the AC scope measurements aren't working well.






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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