You know that the voltage across a capacitor lags the current because the current must flow to build up the charge, and the voltage is proportional to that charge which is built up on the capacitor plates.

 

This calculation works by clicking on the desired quantity in the expression below. Enter the necessary data and then click on the quantity you wish to calculate. Default values will be entered for unspecified quantities, but all quantities may be changed.

 

DC RESPONSE OF CAPACITOR

 

When a battery is connected to a series resistor and capacitor, the initial current is high as the battery transports charge from one plate of the capacitor to the other. The charging current asymptotically approaches zero as the capacitor becomes charged up to the battery voltage. Charging the capacitor stores energy in the electric field between the capacitor plates. The rate of charging is typically described in terms of a time constant RC.