When An Ac Voltage Of 220v Is Applied To The Capacitor

4 min read Jun 26, 2024
When An Ac Voltage Of 220v Is Applied To The Capacitor

Capacitor Behavior under AC Voltage


A capacitor is a fundamental component in electronic circuits, and understanding its behavior under different voltage conditions is crucial for designing and analyzing circuits. In this article, we will explore what happens when an AC voltage of 220V is applied to a capacitor.

Capacitor Basics

Before diving into the specifics, let's quickly review the basics of capacitors:

  • A capacitor consists of two conductive plates separated by a dielectric material, such as air, ceramic, or a polymer film.
  • The plates are charged with equal and opposite charges when a voltage is applied across them.
  • The capacitance (C) of a capacitor is measured in Farads (F) and is determined by the plate area, separation distance, and dielectric properties.

AC Voltage Application

When an AC voltage of 220V is applied to a capacitor, several things happen:

Voltage Across the Capacitor

The AC voltage causes the capacitor to charge and discharge continuously. The voltage across the capacitor (Vc) is equal to the supply voltage (Vs) and is sinusoidal in nature.

Vc = Vs × sin(ωt)

where ω is the angular frequency and t is time.

Current Flow

As the capacitor charges and discharges, a current (I) flows through the circuit. The current is proportional to the rate of change of voltage across the capacitor.

I = C × (dVc/dt)

Since the voltage across the capacitor is sinusoidal, the current waveform is also sinusoidal, but 90° out of phase with the voltage.

Energy Storage and Release

The capacitor stores energy during the positive half-cycle of the AC voltage and releases it during the negative half-cycle. The energy stored in the capacitor (E) is given by:

E = (1/2) × C × Vc^2

The energy is stored in the electric field between the plates and is released back to the circuit as the voltage reverses.

Impedance and Reactance

The impedance (Z) of a capacitor under AC voltage is frequency-dependent and is given by:

Z = 1/(jωC)

where j is the imaginary unit. The reactance (Xc) of the capacitor is the imaginary component of the impedance and is given by:

Xc = 1/(ωC)


In conclusion, when an AC voltage of 220V is applied to a capacitor, it charges and discharges continuously, storing and releasing energy in the process. The voltage and current waveforms are sinusoidal, and the impedance and reactance of the capacitor are frequency-dependent. Understanding these concepts is essential for designing and analyzing AC circuits that involve capacitors.

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