Exactly, for service purposes you don't need any sort of accuracy - and duff caps are mostly MUCH higher than the 1 ohm whit3rd suggested.The answer depends on your ESR resistance range; a CMOS '555 can do a few milliamps of square wave,
and an oscilloscope readout will show resistance at the 0.1 ohm level, but some
low-ESR capacitors are spec'ed for 0.01 ohms (ten milliohms), so a 2%
tolerance means detecting a (0.02 * 0.010amp *0.010 ohms = 2 microvolts)
very tiny step voltage. It would be best to use a four-wire probe for such a measurement.
Large-ish electrolytic capacitors (330 uF) and up that fail due to high ESR are usually
in the 1.0 ohm ++ range, and you don't need accuracy to know that they're bad.
I was just going to send to my PDF of the article that you sent me in 2015 !
Nice!.The scale is the one in the article but I edited it with a bit of software called ' Meter Basic ', quite good.
That's a different circuit. Yours is using a 74HCT14 (presumably a squarewave oscillator, with LPF); Nigel's is using a bunch of opamps (presumably a "sine"wave oscillator).I'm, not sure I remember, but it's unlikely I built it from anything else.
Look Familiar ?
The article from TV Magazine suggests that using a sinewave is advantageous, I've no idea what difference it makes in practice. I'm presuming the multiple 680 ohms (to increase drive power) and 47nF above are to 'round off' the squarewave to approximate a sine?.That's a different circuit. Yours is using a 74HCT14 (presumably a squarewave oscillator, with LPF); Nigel's is using a bunch of opamps (presumably a "sine"wave oscillator).
Is this yours, MM?