Re: CoB LED filament analysis

From	"Don" <g@crcomp.net>
Newsgroups	sci.electronics.design
Subject	Re: CoB LED filament analysis
Date	2026-04-24 17:45 +0000
Organization	A noiseless patient Spider
Message-ID	<20260424c@crcomp.net> (permalink)
References	(7 earlier) <b8ckukt23vpd4eb3sci6cl93vq9mk9d7cr@4ax.com> <20260423a@crcomp.net> <20260423b@crcomp.net> <20260423c@crcomp.net> <10sg8na$3jsof$4@dont-email.me>

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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).
>>
>> Nailed it! The expected curves now appear. Yet, my original current
>> curves are flawless. Filament faffing finally pays off. Uninhibited
>> brainstorming, no matter how insane it is in the interim, imparts
>> insight. Next clue: Bob Pease.

Larkin's correct about one thing. The filament's intrinsic capacitance 
does not play a role in the observed phase shift. 
    When the last paragraph says "expected curves" it means current
curves with zero phase shift relative to voltage. The voltage and current
relationship is totally resistive, as expected.

While perusing TROUBLESHOOTING ANALOG CIRCUITS by Bob Pease for my next
hint, it occured to me how Larkin is the anti-Pease. And it goes a long
way in explaining Larkin's frequent battles with the late, great Jim 
Thompson.

Danke,

--
73, Don, WD7Q                                             veritas    _|_
                                                          liberabit   |
https://www.qsl.net/wd7q                                  vos         |

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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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