A capacitor is an electronic component used to store and release electrical energy. It consists of two conductive plates separated by an insulating material, known as a dielectric. When a voltage difference (potential difference) is applied across the plates, an electric field forms between them, causing positive and negative charges to accumulate on the respective plates.
The capacitor stores energy in the form of electric potential energy within this electric field. The amount of energy a capacitor can store is determined by its capacitance, which is a measure of its ability to store charge. The formula for the capacitance (C) of a capacitor is:
C = ε * A / d
Where:
C is the capacitance in farads (F)
ε is the permittivity of the dielectric material between the plates
A is the area of the plates that overlap
d is the distance between the plates
When you charge a capacitor by applying a voltage across its terminals, electrons accumulate on one plate (negative charge) while an equal amount of positive charge accumulates on the other plate. As the charge builds up, the voltage across the capacitor increases. This process continues until the voltage across the capacitor reaches the same value as the applied voltage. At this point, the capacitor is fully charged.
When you want to release the stored energy, you can connect a circuit to the terminals of the charged capacitor. The stored energy is discharged as the electric field collapses. Electrons flow from the negative plate to the positive plate through the circuit, and the voltage across the capacitor gradually decreases to zero. The rate at which the capacitor discharges depends on the resistance of the discharge path and the capacitance of the capacitor itself.
Capacitors are widely used in electronic circuits for various purposes, such as energy storage, noise filtering, voltage regulation, and timing applications. They play a crucial role in smoothing out power supplies, filtering out unwanted noise, and providing temporary energy reservoirs in devices like cameras, power inverters, and flash units.