• The energy stored on a capacitor is based on the work done by the battery in the circuit.
• The battery voltage represents the energy per unit charge.
• Hence, the work done to move a charge element dq from the negative plate to the positive plate is equal to V dq.
• The voltage is proportional to the amount of charge which is already present in the capacitor.
• Energy stored due to dq = dU = Vdq = q/C dq
• If q is the amount of charge stored when the battery voltage appears across the capacitor, then by integrating the expression, we can get the stored energy.
• U = ∫ dU = ∫ q/C dq integrated between 0 and
• Q = 1/2 Q2/ c = 1/2QV = 1/2 CV2
Energy Stored in a Capacitor.
• A capacitor is a device for storing energy. When we connect a battery across the two plates of a capacitor, it gets charged.
• The work done to charge the capacitor is thus stored in the form of electric potential energy inside the capacitor.
