Why does a capacitor charge itself?

Question

Electronics

There are several large conders on the board, with a capacity of 4000uF, 470uF at 450V. I wanted to call the circuits, but there is some voltage on the diodes on the board and other wiring - about five volts, I looked, it's on the conduits, went for a smoke, came - the voltage is already about seven volts and is slowly growing. No matter how critical, but ringing the board is not so convenient. So this phenomenon became interesting - from what in general can this happen? Payment is off everything. Is it really induced by the EMF from the radio ether? There were no power lines and cell towers nearby, any ideas? :)

Answer 1

This is a property of any dielectric, in it there is a migration of charges from the depth to the electrodes from this, voltage is induced on them, electrolytes are most susceptible to it, film capacitors are smaller, least of all fluoroplastic ones, and even at the same time they change polarity, vacuum ones are free from this drawback.