ceramic capacitor failure rate

[mdanh2002]

Hi,

What is the possibility that through-hole ceramic capacitor may fail in batches after being unused for some years? All are stored at room temperature and not abused

A few years ago I stock various electronics components from eBay at cheap price for my electronics hobby. Things have been going well until recently when I noticed a few simple projects which I could not get working no matter what, even if I have attempted the same project and got it working easily previously.

I suspect the faults with the ceramic capacitors (unlikely but nothing else to suspect). I can test transistors and resistors with my multimeter. Electrolytic capacitors can be tested by charging to 9V and monitor the discharge - slow enough to be observed with my multimeter. Only left with the ceramic capacitors which I have no way to test (except to build circuits which may use other fault capacitors to begin with) - their value too small to apply the same methods. If even a few of them are faulty, I will dump the entire lot and replace - not worth the time troubleshooting problems faulty components may cause.

 

[audioguru]

I never bought no-name-brand junk from E-Bay. Instead I buy name-brand high quality parts from Digikey and every part works perfectly.

I designed a complicated equalizer and had tens of thousands made. They were all tested and sold. Not one failed and not one was returned.

 

[crutschow]

Many multimeters have a capacitance measuring ability.

 

[RCinFLA]

Problems with ceramic disk capacitor usually originate from poor quality outer coating. Poor quality sealing dip allows humidity to get into cap. The metalizing of the ceramic or the wire connection to the metalization on the ceramic can then corrode . Ceramic, depending on the dielectric constant will also absorb moisture. Usually, the higher the relative permeability of the ceramic (for higher capacitance), the more succeptable to moisture intrustion.

 

[mdanh2002]

Hi RCinFLA, thanks for the info. What are the symptoms when ceramic capacitors fail due to absorption of moisture? Is it open circuit, high ESR or high capacitance? I can get a capacitor meter to test all the ceramic capacitors that I have just for the sake of clearing my doubts, but since the meter's testing voltage and frequency is nowhere near the rated values of the capacitor, I am not sure if the problem will emerge. Or do I need an ESR meter?

 

[unclejed613]

the other thing is that a lot of what gets bought cheaply are low voltage ceramics (as in the 25V variety), and these are prone to fail by shorting. i have seen it often enough that i know to look for it when i troubleshoot something that uses them.