Discharging of capacitors

Hi there, the key point of discharging a capacitor is that it discharges through a resistance.

It ‘could’ be a resistance of zero ohms, i.e. a short circuit, and the capacitor would discharge instantly, often with a bang if it was a decent size of a few microfarads, but in the real and theoretical worlds there is usually something called a time-constant of discharge (and also tc of charge) and this happens through a resistance of between a few ohms to a few megohms.

The discharge time of the capacitor & resistance (leads and connectors and actual resistors) in the circuit is then given by tau = c * r

as it (charging & discharging) is an exponential process, with natural logs involved etc, it is traditional to measure the discharge from (say, initial)100% charge level to 36.8% of its initial charge level.

Whilst charging, tend to consider the time taken to go from zero volts to 63.2% of applied DC voltage

See for pictures (of volts & amps) at places like https://www.electronics-tutorials.ws/rc/rc_2.html