Measuring capacitors

Tympanic · 18th May 2010, 03:06 AM

Is there anyone that can help me with measuring capacitors with my voltage/ohm meter? My guitar effect pedal that I built was working one day and the next day it was silent and I suspect one of the caps. is there any way to measure those electrolityc caps? I've been reading allot of ways but people do argue that they work. anyone ?

bob91343 · 18th May 2010, 06:03 AM

There are several ways to measure capacitors but they all require calculation (or a lookup table). You'd probably do it easier just by substituting capacitors. Or spring for a capacitor tester of some sort. (They don't cost much.)

Mooly · 18th May 2010, 06:51 AM

Electroylitic caps are like batteries... when they deteriorate the ESR or equivalent series resistance increases.
So a faulty 100uf cap is still 100uf (in much the same way that a flat 9volt battery reads 9 volts off load), but it's impedance has inceased.

So a meter that reads capacitance is useless for testing quality.

It can be done,
Me and my Tan Theta Meter (Capacitor tester)

but as bob91343 says, just change them and be sure

Enzo · 18th May 2010, 09:48 AM

Why do you think it is a cap? More likely a wire broken off, or other broken connection, or the power connection has failed, especially if it runs through a jack. And semiconductors are less reliable than caps.

Tympanic · 18th May 2010, 03:07 PM

Thanks guys I think I'll go for the capacitor tester. I suspect the capacitor because I turned two of them the wrong way in the beginning, the schematics were wrong,,, so that's why I suspect it,,, couldnt that of damaged the caps? thanks for your help guys

stratus46 · 18th May 2010, 03:45 PM

Quote:

Originally Posted by Tympanic

Thanks guys I think I'll go for the capacitor tester. I suspect the capacitor because I turned two of them the wrong way in the beginning, the schematics were wrong,,, so that's why I suspect it,,, couldnt that of damaged the caps? thanks for your help guys

You'll eventually want a capacitor tester but I assure you capacitors do not fail overnight. Much more likely is something vibrated itself out of a solder connection or flexed enough for metal fatigue. In properly designed electronics the most common failure is electrolytic capacitors. WAY back are semiconductors.

G²

18th May 2010, 03:06 AM	#1
Tympanic diyAudio Member Join Date: Mar 2010 Location: Reykjavík	Measuring capacitors Is there anyone that can help me with measuring capacitors with my voltage/ohm meter? My guitar effect pedal that I built was working one day and the next day it was silent and I suspect one of the caps. is there any way to measure those electrolityc caps? I've been reading allot of ways but people do argue that they work. anyone ?

18th May 2010, 06:51 AM	#3
Mooly diyAudio Member Join Date: Sep 2007	Electroylitic caps are like batteries... when they deteriorate the ESR or equivalent series resistance increases. So a faulty 100uf cap is still 100uf (in much the same way that a flat 9volt battery reads 9 volts off load), but it's impedance has inceased. So a meter that reads capacitance is useless for testing quality. It can be done, Me and my Tan Theta Meter (Capacitor tester) but as bob91343 says, just change them and be sure __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.*

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Measuring an Inductor	Puffin	Parts	2	18th January 2009 10:39 AM
what is the difference between silver mica capacitors and ceramic capacitors ??	prorms	Solid State	1	6th May 2008 12:38 PM
how is it measuring?	fumihiko	Digital Source	18	24th January 2005 04:10 PM
capacitors: panasonic FC vs elna RJH vs rubycon ZA capacitors	costiss	Parts	11	30th January 2003 09:32 PM
differences between computer grade capacitors and small can capacitors	LBHajdu	Pass Labs	0	22nd February 2002 01:29 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

18th May 2010, 06:03 AM	#2
bob91343 diyAudio Member Join Date: Mar 2010	There are several ways to measure capacitors but they all require calculation (or a lookup table). You'd probably do it easier just by substituting capacitors. Or spring for a capacitor tester of some sort. (They don't cost much.)

18th May 2010, 09:48 AM	#4
Enzo diyAudio Member Join Date: Sep 2004 Location: Lansing, Michigan	Why do you think it is a cap? More likely a wire broken off, or other broken connection, or the power connection has failed, especially if it runs through a jack. And semiconductors are less reliable than caps.

18th May 2010, 03:07 PM	#5
Tympanic diyAudio Member Join Date: Mar 2010 Location: Reykjavík	Thanks guys I think I'll go for the capacitor tester. I suspect the capacitor because I turned two of them the wrong way in the beginning, the schematics were wrong,,, so that's why I suspect it,,, couldnt that of damaged the caps? thanks for your help guys

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)