Show My Homework: ECE 210

A 20 $\mu F$ capacitor has a voltage of 12 V across it at t=0. If a constant current of 4 mA flows through the capacitor in the non-passive direction, how long will it take for all of the energy to be drained from the capacitor?

Answer

The current flows in the non-passive direction means that the capacitor is discharging

Initial charge is

$C =Q/U$

$Q =C*U =20*10^{-6}*12 =240*10^{-6} C$

$Q =I*t$

$t = Q/I =240*10^{-6}/4*10^{-3} =60*10^{-3} seconds = 60 mili sec$