A capacitor is a primary storage device widely used to store electric charge or electric energy in electric field and release them whenever required. Almost every electronic device needs Capacitors. Different electric circuits require different kinds of capacitors based on their application types. Some of the various applications of a capacitor used in different electrical industries are discussed below.

A. Energy storage
The primary application of a capacitor is storing electric energy when it is connected to an electric circuit. This capacitor can consume the stored energy after it is disconnected from the circuit and it can work as a temporary battery. Capacitors are usually used in electric devices to control the power supply while batteries are being changed. Therefore, it helps to prevent the loss of data in volatile memory.

B. Smoothing circuits

Most electrical devices make use of d.c. currents, but the current from the mains is a.c. Therefore, a device to convert a.c. to d.c is required. A device called a rectifier is used to convert a.c to d.c. A rectifier will supply a current that varies with time. In a rectifier, there is a system that converts the a.c to a pulsating d.c. Finally, the capacitor converts the pulsating d.c to a smooth d.c. During a cycle, the capacitor charges up when current is supplied and discharges through the load resistor when no current is supplied. The current with the capacitor in place is shown in Figure 13.

C. Filter circuits

Filter circuit is designed circuits in which high-frequency signals travel in one direction in a circuit and low frequencies travel in another. Such a circuit has several applications. For example, in radios or other similar devices, unwanted noise can be diverted from entering a loudspeaker.

Another important application of filter circuit is that when mixed a.c and d.c currents pass through a circuit, the circuit blocks the d.c current and allows only a.c currents to pass through.

D. Tuning circuits

Tuning circuits are combinations of a variable capacitor and a coil, connected in series. A signal of a particular frequency will give a large output.