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ceramic capacitor

john_bry

Oct 31, 2011
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Oct 31, 2011
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is it possible for a ceramic capacitor to be overheated during soldering?
will it fail open or closed?

will an LED fail open or closed?

i am using a pic 12f683 to light some leds but it seems that i get a light but it is draining
the battery within 5 seconds. its like the battery is almost shorting.
whats wierd is the circuit works for about 5 seconds.

thanks for your input
 

davenn

Moderator
Sep 5, 2009
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IC's can partly or totally fail immediately. some times it may take days or weeks to show the failure fault. Its very onpredictable cuz it depends so much on how the heat, excess voltage etc damage affected the IC.

Ceramic caps will fail quite easily with too much heat... they can literally just fall apart

cheers
Dave
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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OK, I see why you suspect the 1uF capacitor. It is the obvious thing across the supply rails.

I've never failed a ceramic capacitor with too much heat and had it go short circuit. But that doesn't mean it won't, although I'd think that failing open or with a much reduced capacitance would be more likely.

I also presume you've read the battery voltage and seen it fall to zero as soon as the power is connected, and also (probably) that the battery gets very hot. These observations would be consistent with your conclusion. To drain within a few seconds, we would also have to assume a very low battery capacity or very low internal resistance (so typically some rechargeable battery).

I would be looking for shorts on my circuit board (I presume it's on a circuit board because you mentioned soldering this component). I'm also envisaging it as a surface mount capacitor because I've not used 1uF ceramics in a leaded form (although they may exist).

If it is a surface mount board, it is possible that you have a misaligned component or a solder bridge causing a short. (the latter is also possible on through-hole boards too)

I would remove the capacitor and see if the problem remains. I would also be testing the impedance across the power supply connections (without a battery) and be expecting a very low resistance if the fault remains.

Images of your board would also probably help.
 
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