Electronics > Beginners
Ceramic capacitor is of too low voltage?...som,etimes blows up at switch on.
Gyro:
--- Quote from: wraper on July 05, 2018, 09:49:06 am ---That was a joke about some insane thread in the past.
--- End quote ---
Yes, there should really have been a smiley on that!
(https://www.eevblog.com/forum/beginners/mains-in-uk-can-go-up-to-292vac-for-periods-of-several-minutes/ for context reference, but please don't resurrect it!)
exe:
Inductive kick of some sort?
mikeselectricstuff:
The fact it goes at switch on suggests to me the issue could be current surge. Regardless of voltage rating, there will always be some peak current value that will make it unhappy.
What limits the peak current into this cap? Is there any series resistance before it?
Gyro:
Of course you don't actually know that it didn't fail short at switch-off, only to manifest itself at the next switch-on.
BrianHG:
Your all crazy, he just needs a 6300vdc cap. There, problem solved... :-DD
Next thing to blow up would be the LR8 linear regulator...
As for inductive kick, not much may be needed at all for such a small cap value while just the AC snap on with capacitance in the diode bridge as well, you can hit a massive combo double peak source voltage, + a super fast V/us slew rate into that poor 1812 cap it you switch on the power at just the right time in the AC phase.
If you are going to stick with this cap, the absolute cheapest thing I would do is add an appropriate sized series resistor either just before the rectifier or just after. However without knowing the rest of the schematic, do not follow me here.
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