Electrical Energy A capacitor can store electrical energy. Connecting it across a resistor or other device discharges it. Across the resistor there is a potential difference that creates the electric current. When the charge in the capacitor decreases, at the same time the voltage decreases. As a result the rate at which the capacitor is discharged, which is the current, is decreased. The outcome of this is that the capacitor will be completely discharged meaning that both the current and voltage will equal zero. At this time all the energy stored in the circuit will have been transferred to thermal energy at the resistor. A heater uses electrical power. The power dissipated