ceramic caps testing

[rummins]

hi all im currently building an esr meter will this be able to check the esr of the caps on my laptop board or would a oscilloscope with a signal generator be a better choice the esr meter im building is the one posted on here under cheaper esr meter

[davmax]

Re: ceramic caps testing

Your title is testing ceramic capacitors. Is this what you are trying to measure?

Ceramics have very low ESR and are very hard to test/measure. Low ESR electrolytics are hard enough. eg if a good electro has 10 milliohm ESR this will require 1 amp to produce a 10 millivolt signal.

This current level would be unusual from a signal generator. Normally this is achieved with pulsed currents in low ESR meters.

Ceramics. Well, typically it is not worth trying, their ESR is so low and they do not degrade like electros and are often low cost to replace.

[rummins]

Re: ceramic caps testing

thanks for the reply all im doing is trying to get my old laptop working playing around really with it as it facinates me to see all those resistors/caps/diodes so as the caps are hard to diagnose i was trying to build something that would check them to see if they are ok

[starfury1]

Re: ceramic caps testing

laptops can be can of worms.

I suppose depending on make model and fault there are common area's of failure.

but as above re ceramic caps

ESR for Electrolytic type caps and then were ESR is more liable to count such as SM-PSU and MB VRM circuts
(on these forums anyway but there are other circuits an devices its good to have one for)

re the Lappy
if you post make model and fault description someone here may be able to tell you your most likely trouble spots.

me, I don't work on them or very rarely anyway

heat is the enemy of these things and power problems or high heat area's
(such as around CPU) I suppose are probably going to be you first ports of call.

But there are some ..well lets say design issues or manufacturing issues that might narrow this

Like one Brand (model(s) ) they was prone to lots dry joints.
So you might be lucky and have a well know fixable issue.


welcome

Cheers