Capacitor
Understanding capacitors, their types, and applications.
What is a Capacitor?
A capacitor is a passive two-terminal electrical component that stores electrical energy in an electric field. It consists of two conductive plates (electrodes) separated by a dielectric (insulating) material. When a voltage is applied across the plates, an electric field is established, and charge accumulates on the plates.
How Capacitors Work
Capacitors store energy by accumulating electric charge. The amount of charge a capacitor can store per unit of voltage across its plates is called its capacitance, measured in Farads (F).
Types of Capacitors
| Type | Description | Common Applications |
|---|---|---|
| Ceramic Capacitors | Non-polarized, small, low cost, wide range of capacitance. | High-frequency circuits, decoupling, resonant circuits. |
| Electrolytic Capacitors | Polarized, high capacitance values, larger size. | Power supply filtering, audio coupling, timing circuits. |
| Film Capacitors | Stable, low loss, good for AC applications. | Filtering, timing, motor run capacitors. |
| Tantalum Capacitors | Polarized, high capacitance in small volume, stable. | Power supply filtering in compact devices. |
| Supercapacitors | Very high capacitance, bridge power gaps, energy storage. | Memory backup, power smoothing, regenerative braking. |
Applications of Capacitors
- Filtering: Smoothing out voltage ripples in power supplies.
- Timing: Used in RC circuits to create time delays.
- Coupling/Decoupling: Blocking DC while allowing AC signals to pass, or suppressing noise.
- Energy Storage: Storing energy for flash photography or pulsed power applications.
- Tuning: Used in resonant circuits for radio and TV tuners.
Frequently Asked Questions
What is the difference between a capacitor and a battery?
Both store energy, but a capacitor stores energy in an electric field and releases it quickly, while a battery stores energy chemically and releases it slowly. Capacitors have much lower energy density than batteries.
Can capacitors be connected in series or parallel?
Yes. When connected in parallel, total capacitance adds up (C_total = C1 + C2 + ...). When connected in series, the reciprocal of total capacitance adds up (1/C_total = 1/C1 + 1/C2 + ...).