DIY capacitance meter?

[NaBo]

hey guys... i've been looking for a capacitance meter for a while, and after searching the boards for a while, it seems a decent one can be ordered for 30 bucks US, pre-shipping.  after shipping and currency exchange, it turns out to be more than i'd wanna spend.

then, while browsing through an electronics store today, i saw a DIY capacitance meter kit, with a digital display and everything included (even an etched PCB and SOLDER!!! ) for 45$ canadian.

i resisted the urge to buy it (for now)...  and the price made it a bit easier... but it got me thinking.  has anyone made one themselves?  kit or no kit?  how does it compare price-wise?  time to build stuff, i have... money for parts i dont.

either way, over 30 bucks for something that just saves me the trouble of being near my laptop to convert codes to values (btw, thanks to whoever posted that link to that electronics assitant program a while back!!!) or figure out what those few old unreadable caps are...

[Jehle]

I remember building one back in college for a lab. I may still have those notes around here somewhere.  If I can round them up, I'll post what I have.

Great idea for project!

[cd]

You know there's lots of mail order sources in Canada so you don't have to deal with cross border shipping, right?  If you're in Toronto, check out Supremetronic on Queen St. West (west of the MuchMusic building, right across from HMV).  You could get an entire digital multimeter with capacitance for under $50CDN.  I can't remember if they have a simple capacitance meter only, but they probably do.

[gak]

http://braincambre500.freeservers.com/indcap.htm

[Fret Wire]

Here's a nice one. I've had one of these for a while, works great.
http://www.electronickits.com/gold/capacitancemeter.htm

[NaBo]

AHHH yes, gak!!! thank you!!!  i had seen something like that before but i forgot where it was... but it was a little curcuit to be able to measure caps with a dmm... very cool!  thanks!!!  i'll have to crunch the numbers to see if its worth building but my guess is that it shouldnt cost more than 5 bucks and a small perf... i like that

[Fret Wire]

That's an interesting link, neat projects. The cap meter project only goes to 2.2uf, though.

[Paul Perry (Frostwave)]

http://earthground.8m.com/indcap.htm
another couple of DIYs, converts your cheapo digital multimeter, one for inductance and one for caps.
Actually, i was helping clean up a deceased estate (two 30 foot skips of rubbish!) and found an old Radio Shack cap meter on the floor (under 4 feet of garbage in a bedroom :shock: ) and it works fine!!

[NaBo]

That's an interesting link, neat projects. The cap meter project only goes to 2.2uf, though.

true, but anything over that is likely gonna be an alumelectro and thus be clearly labelled... no sketchy coding to decipher ... i really just want something dirt cheap that will allow me to identify ceramics, tants and films without having to look em up or think too much, or the odd one where the code makes no sense, has rubbed off, etc.  also, i get a few of my less common values (example, the 0.0039 uf ceramic in the green russian big muff) from an electronics surplus store, cuz they pretty much have every possible value of every type there... so i'd like to be able to just check those out before using them.

http://earthground.8m.com/indcap.htm
another couple of DIYs, converts your cheapo digital multimeter, one for inductance and one for caps.

thanks Paul Perry of Frostwave fame (geez, does anyone else feel like they're hob-nobbing with royalty on this forum sometimes???), but gak beat ya to it a few posts ago

but how about that cap meter find??? wow. so many people seem to find treasures in dumpsters and stuff... i wish i had that kind of luck.  :?

[Paul Perry (Frostwave)]

I must confess, if i spent as much time in a job as I do in dumpsters and thrifts, i'd be a WHOLE LOT richer.. but the atmosphere in a dumpster is usually better & you meet a nicer class of people :wink:
BTW if you type "capacitance meter" into Google images, you get a lot of fun stuff, includign a DIY cap meter that measures down to 1pf with 1% accuracyat 1 pf!!!  think if I ever get sick of fx boxes i could collect capacitance meters! seems to bring out the weird in eople, the same way as boxes.

[Fret Wire]

Nabo, there are plenty of tants that go over the 2.2uf range also. Not always clearly marked. Plus, there is also the checking of tolorance and drift (not just value) of larger caps that the project can't do. On vintage amps and pedals that have drifted to a sweet spot, it's nice to accurately measure what the caps have drifted to. I work on amps also, so the project would be useless for amp work. Heck, it can't even measure the polor cap in a wah. For only $29, it's more cost and time effective to buy a meter that can cover the full range of caps for pedals and amps. Very good bang for the buck.

The inductance project is also nice, but only measures up to 7mh, not enough to measure a wah inductor. For $42, you can get a cap/inductance meter that covers 1pf-200uf caps and inductance from 1uh to 2H
http://circuitspecialists.com/prod.itml/icOid/3394

Like I said, they're nice projects, but sometimes it's better to buy than build.

[Nikolay]

This is perfecr proffesional LCR meter (I wish to make it)

http://www.circuitcellar.com/PSOC2002/winners/h3.htm

[NaBo]

finally got this project outta the way, and it works great.  pretty darn accurate and under 5 bucks to build!  i made a perf layout for my own purposes, but i'll post a link to it for anyone else who doesnt wanna bother figuring one out: http://img.photobucket.com/albums/v515/Nabotics/capmeterlayout.gif

and here's a pic of the finished thing, just for fun!