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Can capacitors create short circuits?

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ferbo

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Hi,

I have a Vesc module which is faulted. I have noticed that it's 3.3v and GND is shorted while testing with multi meter. other than the IC s the only components between the two nets are the capacitors.
My question is that is it possible that a capacitor is burnt and short circuited?

Thank you very much for your help guys.

Best,
Ferbo
 

Definitely possible, e.g. in case of broken MLCC, altough open circuit is more likely. PCB shorts are possible as well. You can try to locate the short by supplying a limited current to the board (e.g. 1-2 A, whatever applicable) and measure trace/plane voltage drop with a sensitive multimeter.
 
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    ferbo

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The multimeter should measure the resistance between both nets (3v3 and GND) applying and small voltage and dividing voltage by current. As any capacitor is initially unloaded, you will always get an initiall short-circuit measurement, that progressively moves towards an open-circuit. I assume you mean that you are getting a continuous and prolonged short-circuit measurement. Is that correct?

If that is the case, then I see two options:
- You really have a damaged short-circuited capacitor
- There is something else in the board that is doing the short-circuit. It might be something broken, like a track, a via or a tin ball that don´t see anywhere.

In any case FvM advice to locate the short is great.
 
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    ferbo

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Try removing each capacitor in turn to determine if any have short circuited.
If removing the caps makes no difference, then it's definitely something else.
Possibly the power to theIC/s, if they use the 3.3 volts as Vcc.
Regards,
Relayer
 
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    ferbo

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Some capacitors like antalum has polarity. In case of wrong connection it can be a source of high current between supply and ground.
Other source can be an ESD diodes in the IC, again in case of mismatched connection.
 

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    ferbo

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yes today a capacitor (usually smd) can be the source of a short. it can be mlcc or tantalum, but mainly smd.

here is a simple tool to build to find the shorted component easy and fast
**broken link removed**
 
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    ferbo

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I had a display power supply failure in an old VCR I had.
While poking around the innards while the unit was on, I nearly burnt my finger on a small electrolytic capacitor can.
It obviously had a low resistance short and drawing so much current that it became quite hot.
Not hard to determine the power supply problem in that case.
I replaced the cap and everything again worked fine.
 
Dear friends,

I unmounted all the related caps and checked them the problem was neither of them. then I moved on to the chips and finally unmounted my main processor IC which was the issue. its vDD and Vss were shorted internaly; which I'm guessing had happened because of an external metal touching my circuitry and shorting something and damaging the chip in process.

Any ways thank you all.
 

Hello



I am mr.doosti engineer



From IRAN-MASHHAD-FANAVARAN COMPANY



In designing the 7 watt LED driver , I used IC BP3133A , but under the LOAD of a 1uf



Capacitor connected to a 2 IC pin . THE capacitor is short- circuited, which works by replacing that circuit again .

OF course, this problem occurs in some drivers .

THANK YOU for helping me fix these bugs.


[Moderator action: removed email address]
 
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