Capacitor

In Electronic Circuits, Capacitor is a standard component that is used to store electric charges. As capacitors cannot control or increase the current flow in a circuit they are called Passive Electronic component. They are used to build Electronic Hardware.

Capacitance is the measure of ability of a capacitor to store charge. And farad is the measuring unit. Capacitor does not heat up like other passive electronic components and are thus more efficient. When current is passed through the circuit, the capacitor takes the varying current in and gives a smooth current out. Thus, it acts as a supplier of smooth current.

Capacitor, when connected in a DC circuit blocks the flow of current through it. But when connected in an AC circuit, allows current to flow through it with little or no resistance. If a DC voltage is applied the capacitor becomes fully charged until it either leaks or intentionally discharged. On the other hand, capacitor will pass an AC voltage as varying electric field is set up in its plates. Thus, they help in converting AC electricity to DC electricity and maintain a steady voltage.

If capacitors are connected in series, then the overall capacitance decreases whereas if it is a parallel connection, the overall capacitance increases. Electrolytic capacitors have polarity whereas non-electrolytic capacitors don’t. Depending on the type of dielectric used capacitors are classified as air-gap, tantalum bead, ceramic, paper, polyester, glass, oil, vacuum capacitors and many more. Depending on the types, capacitors perform a variety of tasks like coupling, de-coupling, filtering which are used in timing circuits, sensing and in recent communication equipments.

Questions:

• What is a capacitor?
• Define the working pattern of capacitors in AC and DC?