vinodh kumar
Last Activity: 9 Years ago
here we use some terminology...
t=0- means the time just before the switch is closed/opend depending on the previous position.
t=0+ means the time just after the switch is closed/opend depending on the previous position.
now for the above circuit at t=0- there is no charge on the capacitor. so V- = 0 volts
that is voltage just before closing the switch.
we know from the continuity of charge , Q+ = Q - that is
the charge present on the capacitor plates just before closing the switch should always be equal to charge that is present on the capcitor plates just after teh switch is closed.
so V + = V -
so V + =0 volts. here V – voltage across capacitor.
At t=0 + capacitors are replaced by short circuits( V=0) then it becomes resistive network. we can easily solve that resistive network for the current.