Question

The voltage across a 5microF capacitor change uniformly from 10 to 70V in 5ms. Calculate the change in capacitor charge and charging current.

Answer 1

Given

c = 5μF

t = 5ms

ΔV = 10 to 70V

change in capacitor charge Δq = cΔV

= 5 x 10^-6 (V_f - V_i)

= 5 x 10^-6 (70 - 10)

= 300 x 10^-6

Δq = 0.3 mC

change in current i = c dv/dt

i = 5 x 10^-6 x \(\frac{60}{5\times10^{-3}}\)

i = 60 x 10^-3

i = 60 mA