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NNTP-Posting-Date: Tue, 09 Apr 2024 14:21:10 +0000
From: John Larkin <jl@997PotHill.com>
Newsgroups: sci.electronics.design
Subject: Re: Inductance meter for BIST
Date: Tue, 09 Apr 2024 07:19:26 -0700
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On Mon, 08 Apr 2024 17:17:15 -0700, john larkin <jl@650pot.com> wrote:

>I can build this into my new programmable inductor module, for
>self-test. With a 1% cap, it should be plenty good. L range will be
>750 mH down to maybe 10 mH, part of simulating solenoids and torque
>motors and such.
>
>If I add a switch to open R3 and run some current through R1, it can
>measure series resistance too.
>
>https://www.dropbox.com/scl/fi/tn8lpk38677ioylhdkget/P955_L-meter.jpg?rlkey=xynqyzfc2x020llr3a945c0td&raw=1
>
>https://www.dropbox.com/scl/fi/gojlqxj23r4m57ke9jhui/Ind_Meter_1.asc?rlkey=if40kmtiz49gp62bacfvju3uv&dl=0

Most L-meters, the AADE sort, lie or don't work with big Ls.

This is better:

https://www.dropbox.com/scl/fi/9tex1slpnaqz4n2cbxp3n/Ind_Meter_Apr_9.jpg?rlkey=52vbyylc5ax48w54qdxm9r9cq&raw=1

Given a small uP, like the Rasp Pi thing, it could measure L and Rl
pretty easily. One could get compusive and math out the small
inductance measuring error from the inductor copper resistance.

I need repeatability more than accuracy, and don't have time to
explore this very deep, but it's interesting.

I've been buying shaftless torque motors off ebay, to understand them
electrically. We need to simulate a torque motor.