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# What is the working principle of a capacitor?

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## Capacitor:A capacitor is a device that is used to store charges in an electrical circuit. A capacitor works on the principle that the capacitance of a conductor increases appreciably when an earthed conductor is brought near it. Hence, a capacitor has two plates separated by a distance having equal and opposite charges. The space between the conductors may be filled by vacuum or with an insulating material known as a dielectric. The ability of the capacitor to store charges is known as capacitance.Equation of capacitance is given by, $q=CV\left[q=charge,C=capaci\mathrm{tan}ce,V=voltage\right]$Working principle of a capacitor:Consider the following circuit, which shows the working principle of a parallel plate capacitor with a dielectric between them. Apply the voltage V as shown in the circuit, with plate 1 being positive and plate 2 being negative. An electric field appears across the capacitor. When the voltage is supplied to these plates, plate 1 will carry a positive charge from the battery, and plate 2 will carry a negative charge from the battery. The voltage is supplied for a period of time, during which time the capacitor is charged to its maximum holding charge, and this period is referred to as the capacitor's charging time.After a period of time, when the capacitor has reached its full charging capacity, we will turn off the electricity to the capacitor. The two plates have a negative and positive charge for a period of time. As a result, the capacitor serves as a source of electricity. If these plates are connected to a load, current flows from plate 1 to plate 2 until all charges on both plates have been dissipated. The time it takes for the capacitor to discharge is referred to as the dissipation time.

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