What is electric breakdown? Can anyone explain it briefly? The results from Google are too complicated and not understandable.

its when an insulator fails to prevent the flow of electricity.

 

lets say you have two electrodes sandwiching a layer of rubber. apply a voltage and you won't get any current because all the electrons in the rubber are tied into the rubber molecules tightly and they can't move.

 

as you increase the voltage across the rubber the electrons will get pulled by the electrostatic force more and more.

 

eventually you'll reach a point where the voltage from the electrodes is enough to rip the electrons from the molecules and let them free to move. When this happens you get a dielectric breakdown.

 

its typically a cascading avalance like effect, the first free electron knocks a second electron off its molecule and then you have two, those two each knock an electron off etc. etc.

 

once you have this flow of electrons, the voltage will drop sharply and you'll be able to conduct electricity through the insulator at a lower voltage than the breakdown.

If you want a fun fact: consider for a moment why the terminals of a plug are separated the way they are.

In a sense, electric breakdown happens with "static" electricity as your hand approaches a doorknob, etc. The air acts as an insulator until the gap narrows enough for the charge to break down the insulating properties of the air.

God bless the people answering me.