What is a Capacitor?

A capacitor is an essential electronic component used to store electrical energy. It consists of two conductive plates separated by a dielectric material. Here are the key points:

  1. Structure:

    • A capacitor typically has two terminals (positive and negative).
    • The conductive plates can be made of metal foil, film, or other materials.
    • The dielectric (insulating material) prevents direct contact between the plates.

  2. Working Principle:

    • When a voltage is applied across the terminals, an electric field forms across the dielectric.
    • Positive charges accumulate on one plate, while negative charges accumulate on the other.
    • The capacitor stores energy in this electric field.

  3. Capacitance:

    • The capacity of a capacitor to store charge is measured in farads (F).
    • Capacitance depends on the surface area of the plates, the distance between them, and the dielectric material.

  4. Applications:

    • Filtering: Capacitors smooth out voltage fluctuations in power supplies.
    • Tuning: In resonant circuits, capacitors help tune radios to specific frequencies.
    • Energy Storage: Capacitors store energy for short bursts (e.g., camera flashes).

  5. History:

    • The earliest capacitors were Leyden jars (water-filled glass jars) created in the 1740s.
    • Today, capacitors play a crucial role in electronics, from power transmission to digital memory.

Remember, unlike resistors, capacitors don’t dissipate energy—they store it!