Jameco DIY Capacitor Tester

[liquids]

It won't tell you the value in numerical format, but if you have some reference caps, it looks like this can be useful, and maybe a little more fun than your average cheap DMM with capacitance measurement.    And fun with electronics - that's the point around here........right?   

http://www.jameco.com/Jameco/workshop/MyStory/captester.html?sp_rid=MTgyNDYxNDI5MDES1&sp_mid=3910917

[deadastronaut]

cool...beep beep.....beeeeep beeeeep.....

[DavenPaget]

Surely i want a http://www.goodluckbuy.com/lc200a-high-precision-inductance-capacitance-meter-l-c-meter-.html DIY Version ( Maybe kit instead ... )

[CynicalMan]

It would be neat to make this and then run it into a software frequency detector to measure precisely.

[PRR]

> run it into a software frequency detector to measure precisely.

In audio we never need to know our caps closer than 10%.

If you know any musicians (might be some around here), they can ear-pick tones better than 6%, often better than 1%.

Listen to the 1,000pFd standard cap. Now the unknown cap. If it sings an octave higher it is 500pFd. If it sings an octave and one semi-tone higher, it is near 470pFd, but we don't care 500 or 470 so we don't care about a semitone or two.

EDIT.... I thought this thing sang steady. I now see it "chirps". That will be much harder to ear-match. You might just do a stock 555 astable to get a steady tone.

[CynicalMan]

Fair enough, but in terms of convenience, having a digital readout would be nice. I was thinking of something that would compute the capacitance based on the input frequency. Maybe something like this would work better for that, not having to drive a speaker:

[O]

I built this one:

http://www.sparkfun.com/products/9485

It was cheap enough to try and it actually works really well especially if you box it up in a metal enclosure (I used a 1590BB).

[PRR]

There's 6 million ways to measure caps in the naked city.... oh, wrong story.

Why produce a frequency then measure it? Who has a frequency meter?

Lots of ways to get to a voltage. Any serious hobbyist has a voltmeter.

eBay has direct readout cap-testers around $30 (and lower and higher).

The SparkFun kit looks good (though out of stock today).

DIY:

http://freecircuitdiagram.com/2009/05/10/capacitance-meter/

http://hmin.tripod.com/als/andysm/pages/tstgear8.html#TST811

http://test-equipment.blogspot.com/2009/06/capacitance-meter.html

[deadastronaut]

or a set of drawers...

[PRR]

http://www.seeedstudio.com/depot/capacitance-meter-kit-p-268.html?cPath=174