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Topic: Capacitor overheats (Read 607 times) previous topic - next topic

rickduley

I have made a Shield for a UNO to the circuitry in the attachment.  I power it with a standard 9 V battery and it connects with the other boards in the RC network just fine.  However, after a minute or so the capacitor is far to hot to handle and the communication dies.

Is there some obvious reason (given that the board complies with the circuit diagram) for the overheating and consequent failure?

Thanks



saximus

Is it an electrolytic capacitor? Is it oriented correctly? What is its voltage rating?

aarg

Tantalums overheat when they're reversed. The really nasty thing is that they do it randomly - they may run fine backwards for hours or weeks and then suddenly begin to fail.
  ... with a transistor and a large sum of money to spend ...
Please don't PM me with technical questions. Post them in the forum.

larryd

"suddenly begin to fail."
Smoulder, catch fire, explode into many pieces.


.
No technical PMs.
The last thing you did is where you should start looking.

PaulMurrayCbr

What everyone else said - capacitor wrong way around.
http://paulmurraycbr.github.io/ArduinoTheOOWay.html

srnet

Exploding capacitors, usually caused by fitting them reversed, can cause nasty eye injurires.

At least for the first time you connect up a new circuit, put a pair of safety glasses on.
$50SAT is now Silent (but probably still running)
http://www.50dollarsat.info/
http://www.loratracker.uk/

Budvar10

Arduino clone with ATmega1284P   http://forum.arduino.cc/index.php?topic=277260.0

TomGeorge

I have made a Shield for a UNO to the circuitry in the attachment.  I power it with a standard 9 V battery and it connects with the other boards in the RC network just fine.  However, after a minute or so the capacitor is far to hot to handle and the communication dies.

Is there some obvious reason (given that the board complies with the circuit diagram) for the overheating and consequent failure?

Thanks



Hi,
Can you post a picture of the shield and indicate the capacitor that is over heating please.
Thanks.. Tom.. :)
Everything runs on smoke, let the smoke out, it stops running....

rickduley

Can you post a picture of the shield and indicate the capacitor that is over heating please.
Capacitor on left.

larryd



There is a yellow tantalum capacitor on the left.
Make sure polarity is correct and it has a sufficient voltage rating.


.
No technical PMs.
The last thing you did is where you should start looking.

TomGeorge

#10
May 21, 2017, 02:58 am Last Edit: May 21, 2017, 02:59 am by TomGeorge
Hi,
If cap 3 is the offending component, then it may be in the wrong way, or just failed during operation.

Is it the 10uF added for the nrf unit?
Tom... :)
Everything runs on smoke, let the smoke out, it stops running....

rickduley

Is it the 10uF added for the nrf unit?
Yes.  It's the nRF capacitor.

If cap 3 is the offending component, then it may be in the wrong way, or just failed during operation.
It was the wrong way round.  Thanks to all you people who replied.



larryd

Quote
It was the wrong way round.
You are very lucky.

Throw the old one away.


.
No technical PMs.
The last thing you did is where you should start looking.

Whandall

If the capacitor is for the NRF, it should be placed as close as possible to the chip,
the connector pins with adjacent 3.3V and GND are a good place to solder it to.

A small SMD type fits best.  ;)
Ah, this is obviously some strange usage of the word 'safe' that I wasn't previously aware of. (D.Adams)

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