Difference Between Capacitor and Battery

Capacitor vs Battery

Capacitor and battery are two electrical components used in circuit design. Battery is an energy source, which injects the energy into to circuit, whereas capacitors are passive devices, which draw energy from the circuit, store and then release.


Capacitor is made of two conductors separated by an insulating dielectric. When a potential difference is provided to these two conductors, an electric field is created and electric charges are stored. Once the potential difference is being removed and two conductors are connected, a current (stored charges) flows to neutralize that potential difference and electric field. The rate of discharge gets reduced with time and this is known as the capacitor discharging curve.

In analysis, capacitor is considered as an insulator for DC (direct current) and conducting element for AC (alternating currents). Therefore it is used as a DC blocking element in many circuit designs. Capacitance of a capacitor is known as the capability to store electric charges, and it is measured in the unit called Farad (F). However in practical circuits, capacitors are available in the ranges of micro Farads (µF) to pico Farads (pF).


Batteries are used as energy sources in electrical circuits. Usually, a battery provides a constant potential difference (voltage) between two ends and supplies a direct current (DC). The potential difference provided by a battery is known as its ‘electromotive force’ and measured in Volts (V). Therefore, batteries are usually DC elements. However DC supplying batteries can be converted into AC using a circuit called inverter. Therefore, batteries with built in invertors are available in market, and they are called ‘AC batteries’ which act as an AC source.

Energy is stored inside the battery in the form of chemical energy. It converts into electrical energy at the operation. Once a battery is connected to a circuit, a current emits from the positive electrode (anode), travels through the circuit, and comes back to the negative electrode (cathode). This is called discharging function of the battery. After discharging for a long period, stored chemical energy reduces to almost zero, and it has to be recharged. Some batteries are not rechargeable, and they should be replaced with a similar one.

What is the difference between capacitor and battery?

1. Battery is a source of energy for a circuit, whereas capacitor is a passive element, which draws energy from the circuit, store and release it.

2. Usually battery is a DC component, whereas capacitor is mostly used for AC applications. It is used to block DC components in circuits.

3. Battery provides a relatively constant voltage when discharging, whereas discharging voltage gets rapidly decreased for capacitors.