https://www.xyphro.de/blog/index.php Copyright 2026, Kai Gossner xyphro@gmail.com (Kai Gossner) en-US SPHPBLOG 0.8.1 https://www.xyphro.de/blog/index.php?entry=entry121104-191328 Basically it is an effect that each capacitor has. Depending on the dielectricum it is larger or smaller.

When a capacitor is discharged the capacitor charges up again after removing the shortcut between the 2 terminals.

Of course I had to test it myself :-)

My test setup:



The device under test is a 220µF SMD Tantal capacitor from a junkbox.

I connected a scope (10 MOhm input impedance) to the 2 terminals and charged the capacitor up to 10V.

I discharged the capacitor with a 680 Ohm resistor. As soon as 0V was reached I removed the resistor and watched the scope:



Cool, it really charges up! After a few seconds it looked like this:



So the capacitor charged "itself" to 280mV!

It does not matter how the capacitor is discharged, even a direct shortcut leads to the same result.

Apart from things like piezoelectric effects this is also something that has to be considered in some electronic circuits (e.g. integrators)...
]]> interesting observations https://www.xyphro.de/blog/index.php?entry=entry121104-191328 xyphro@gmail.com (Kai Gossner) Sun, 04 Nov 2012 18:13:28 GMT