Capacitors are commonly employed in the construction of various electronic circuits. A capacitor is a two-terminal passive electrical component that may electrostatically store energy in an electric field. It functions as a miniature rechargeable battery that stores electricity in simple terms. Unlike a battery, though, it may charge and discharge in a fraction of a second.

A. Structure

Capacitors exist in a variety of sizes and designs, but they all share the same basic components. A dielectric or insulator layered between two electrical conductors or plates separates them. Plates are made of conductive materials like thin metal sheets or aluminium foil. A dielectric, on the other hand, is a non-conducting material like glass, ceramic, plastic film, air, paper, or mica that does not conduct electricity. The two electrical connections protruding from the plates can be used to connect the capacitor to a circuit.

B. What Is It and How Does It Work?

An electric field forms across the insulator when you supply voltage to the two plates or link them to a source, causing one plate to build positive charge while the other accumulates negative charge. Even if the capacitor is disconnected from the source, it retains its charge. When you connect it to a load, the capacitor’s stored energy will flow to the load.

The quantity of energy held in a capacitor is known as capacitance. The capacitance of a device determines how much energy it can store. Moving the plates closer together or increasing their size will increase the capacitance. You can also improve the capacitance by improving the insulating properties.

C. Purpose and Importance

Despite their appearance, capacitors can serve a variety of purposes in a circuit, like blocking direct current while allowing alternating current to pass or smoothing the output of a power source. They’re also utilised to keep voltage and power flow stable in electric power transmission systems. Power factor adjustment is one of the most important roles of a capacitor in an AC system; without it, single phase motors would not have enough starting torque.

Capacitor Applications Filters

If you’re using a microcontroller in a circuit to run a certain programme, you don’t want the voltage to drop since the controller will reset. It is for this reason that designers utilise a capacitor. It can provide the necessary power to the microcontroller for a fraction of a second to avoid a restart. In other words, it stabilises the power supply by filtering out noise on the power line.

Applications for Hold-Up Capacitors

A capacitor, unlike a battery, releases its charge quickly. It’s for this reason that it’s utilised to temporarily energise a circuit. The capacitor attached to the flash gun is charged by the batteries in your camera. When you snap a flash photograph, the capacitor’s charge is released in a fraction of a second, resulting in a burst of light.

Applications for Timer Capacitors

Capacitors are employed as a timing element in a resonant or time-dependent circuit, together with a resistor or inductor. The circuit’s operation is determined by the time it takes to charge and discharge a capacitor.


A resistor is a two-terminal passive electrical device that opposes current flow. It is most likely the most basic component in an electrical circuit. Resistance is present in practically all electronic circuits, making it one of the most prevalent components. Typically, they are color-coded.