- Richard Trimble
A constant voltage is applied to the circuit shown which contains two resistors, a multi-way switch and a capacitor. Initially open, the switch is closed to the left for a time and then closed to the right for a further time , before being set to open. Express the voltage across the capacitor as a function of time.
In the first phase with the switch to the left we have a charging RC circuit At the end of this time the charge on the capacitor is . This forms the initial charge for the second phase with the switch to the right. This is now a discharging RC circuit. Note that we have used because time in this section is running from to . Use the interactivity below to investigate how the final Voltage on the capacitor varies with , , and .