Beginner measures capacitor with Fluke 17B

[easilyconfused]

Per instructions included with 17B Fluke: turned dial to capacitor check mode with red lead in capacitor check socket (V) and black lead in com socket. Display showing steady value of 0.47nF with no capacitor connected. Connected red lead to + leg of 47.0uF cap, black to - leg. Value displayed persists at 0.47nF. Shorted across legs to discharge any charge. Displayed value changes to 0L.uF. Maintained connections for more than 15 seconds per instructions. Display unchanged. Capacitor is known to be good as evidence by its ability to develop voltage on breadboard. Any explanations for meter results will be appreciated.

[easilyconfused]

I had never checked a cap before. After trying it, then posting my question, then Googling the process, it seems that checking caps with a mm is a joke. Best I can tell from Googling- you need an ESR. And they're pretty expensive. For the time being I'll assume that cap checking is beyond the scope of my beginner experiments. I'll replace the ones that are leaking goo or have some other obvious problem and assume that all others are working properly.

PS: If what I have stated is true- cap testing as a mm feature should probably be given little value in reviews.

[easilyconfused]

I'm forever dreaming up contraptions that ultimately turn out to be useless. I was wondering if this might double as a pretty good cap checker and educational tool. All I know about capacitors I learned today so keep that in mind as you wonder what's going on in my head. It would be used in conjunction with a multimeter. When the start button is pushed it runs for five seconds then freezes the voltage reading. And, of course, I wouldn't have a clue how to build it.

[NiHaoMike]

A good way to measure ESR is with a signal generator, oscilloscope, and a known (low value, less than 100 ohms) resistance.

[saturation]

To measure capacitance directly, not its ESR you can:

https://www.eevblog.com/forum/index.php?topic=909.msg11424#msg11424

or with a good function generator via:

https://www.eevblog.com/forum/index.php?topic=533.msg7756#msg7756

[ModemHead]

Measuring a capacitor below 1 nF (0.001uF) with a multimeter is a challenge, but if your multimeter does not read somewhere around 47uF with a 47uF capacitor attached, the capacitance measuring function is definitely broken.  A pair of very short test leads (~150mm or so) with alligator clips will yield best results.