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Groups > sci.electronics.design > #743433
| From | "Don" <g@crcomp.net> |
|---|---|
| Newsgroups | sci.electronics.design |
| Subject | Re: CoB LED filament analysis |
| Date | 2026-04-26 19:22 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <20260426e@crcomp.net> (permalink) |
| References | (11 earlier) <10skrd7$1fnd2$1@dont-email.me> <20260426a@crcomp.net> <20260426b@crcomp.net> <20260426c@crcomp.net> <10sljo0$1fnd2$2@dont-email.me> |
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 |
Back to sci.electronics.design | Previous | Next — Previous in thread | Next in thread | Find similar
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
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Re: CoB LED filament analysis "Don" <g@crcomp.net> - 2026-04-24 20:15 +0000
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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
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Re: CoB LED filament analysis piglet <erichpwagner@hotmail.com> - 2026-04-26 19:17 +0000
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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
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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
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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
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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
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