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Topic: A capacitor is charged and discharged every 0.01 s (Read 1 time) previous topic - next topic

hanyc93

What would possibly happen if a capacitor is charged and discharged every 0.01 seconds?

--> I'm worried whether the capacitor would explode?

westfw

It depends on the currents involved, but the rate itself is nothing remarkable.  There are frequently capacitors in the output stages of amplifiers, and they essentially charge and discharge at audio (.0001s) or RF (0.000001) rates ...

majenko

If the voltage you are using are within the tolerance of the capacitor then what will happen if it charges and discharges tens, hundreds, thousands or millions of times per second?  Well, quite simply, it charges and discharges tens, hundreds, thousands or millions of times per second.

That's what capacitors do.

If you have too much voltage, regardless of how frequently you charge or discharge, then it can and will explode.
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jackrae

This site frequently use terms such as "explode" and "go on fire" or "burst into flames"

Having been professionally involved in the electronics game in one sense or the other for almost 60 years I have experienced capacitors "popping", "bursting" or "leaking";  resistors "smoking";   semiconductors "popping" and "smoking" and various components glowing rather well  --  but  NEVER "exploding", "going on fire" or "bursting into flames"

I fear there are too many out there who are either overly cautious or trying to scare the living daylights out of those who wish to learn.

So, FEAR NOT, exercise caution, destroy a few components, be prepared to turn off the power when the magic smoke starts to appear, but, most of all,  have FUN experimenting !!

pito

#4
Jan 09, 2014, 06:11 pm Last Edit: Jan 09, 2014, 06:14 pm by pito Reason: 1
Quote
If the voltage you are using are within the tolerance of the capacitor..

And currents too.. Wires inside the capacitor may burnout when the currents are too high. Ie. you may have an 100mF/100V capacitor, when charged and discharged by a current of 100A 10x per second to 99V it may smoke too..
Another corner case  :P

Quote
have FUN experimenting !!

Yes! In a controlled environment, however..
:)

westfw

It depends on your definition of "explode."  I've seen/heard electrolytic caps go "bang" (louder than a "pop"), yielding some confetti and sending the casing flying, and even overpowered LEDs send pieces flying with enough violence to make admonitions to wear safety glasses ALL THE TIME seem reasonable...

fungus

#6
Jan 09, 2014, 07:23 pm Last Edit: Jan 09, 2014, 07:25 pm by fungus Reason: 1

It depends on your definition of "explode."  I've seen/heard electrolytic caps go "bang" (louder than a "pop"), yielding some confetti and sending the casing flying


Those things produce "explosions" by any definition (and the flying cases can leave dents in plaster walls).

There's plenty of videos on youtube:
https://www.youtube.com/watch?v=ToWsF3HcQUU
https://www.youtube.com/watch?v=B8gFgIQl2HI
https://www.youtube.com/watch?v=_WheLp0RdLQ

No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

westfw

Quote
I've seen/heard electrolytic caps go "bang"

WITHOUT being intentionally abused.  Inserting an electrolytic backwards can be sufficient, given a reasonably beefy power supply.

majenko

I used to blow up model trains using capacitors connected backwards... it was fun ;)
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MarkT

Capacitors usually have a working voltage spec and a ripple-current spec, the latter
being the max RMS current they can take continually.

Electrolytic capacitors are scored on the end to weaken the case and control any explosion
and reduce the risk of shrapnel.  They explode because of overheating boiling the electrolyte
I think.

Exploding power MOSFETs isn't that hard to achieve in my experience.

Eye protection is something I'd always recommend when working closely with
high power electronics, because of the risk of failed components or big sparks.
[ I won't respond to messages, use the forum please ]

cjdelphi


This site frequently use terms such as "explode" and "go on fire" or "burst into flames"

Having been professionally involved in the electronics game in one sense or the other for almost 60 years I have experienced capacitors "popping", "bursting" or "leaking";  resistors "smoking";   semiconductors "popping" and "smoking" and various components glowing rather well  --  but  NEVER "exploding", "going on fire" or "bursting into flames"

I fear there are too many out there who are either overly cautious or trying to scare the living daylights out of those who wish to learn.

So, FEAR NOT, exercise caution, destroy a few components, be prepared to turn off the power when the magic smoke starts to appear, but, most of all,  have FUN experimenting !!


That's true... but you know what you're doing, tell me what happens if you use a 5v rated cap in a 12v circuit like some here would and do....

majenko



This site frequently use terms such as "explode" and "go on fire" or "burst into flames"

Having been professionally involved in the electronics game in one sense or the other for almost 60 years I have experienced capacitors "popping", "bursting" or "leaking";  resistors "smoking";   semiconductors "popping" and "smoking" and various components glowing rather well  --  but  NEVER "exploding", "going on fire" or "bursting into flames"

I fear there are too many out there who are either overly cautious or trying to scare the living daylights out of those who wish to learn.

So, FEAR NOT, exercise caution, destroy a few components, be prepared to turn off the power when the magic smoke starts to appear, but, most of all,  have FUN experimenting !!


That's true... but you know what you're doing, tell me what happens if you use a 5v rated cap in a 12v circuit like some here would and do....

You experience a "catastrophic venting event".
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cjdelphi


hanyc93


westfw

Quote
My problem is solved

Aw, man...  Does that mean we have to stop talking about EXPLOSIONS?

You might want to note that a typical plug-in power supply feeds the caps from a 120Hz rectified sine wave.  They're not supposed to discharge all the way every cycle, but they do charge and discharge SOME at about the  rate you are talking about.

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