Capacitor

Definition

A capacitor is an electrical component that stores energy in the form of an electric field, created between two conductive plates separated by an insulating material. It is used to temporarily hold charge and release it when needed.

5 Must Know Facts For Your Next Test

1. The capacitance of a capacitor is measured in Farads (F) and depends on the surface area of the plates, the distance between them, and the dielectric material used.
2. Capacitors can be connected in series or parallel configurations, affecting the total capacitance of the circuit.
3. In alternating-current (AC) circuits, capacitors create a phase shift between voltage and current.
4. The energy stored in a capacitor is given by $E = \frac{1}{2}CV^2$, where $C$ is capacitance and $V$ is voltage.
5. Capacitors are often used for filtering applications in AC circuits to block direct current (DC) while allowing AC signals to pass.

Review Questions

• What factors determine the capacitance of a capacitor?
• How does connecting capacitors in series differ from connecting them in parallel?
• What role does a capacitor play in an AC circuit?

Related terms

Dielectric:

An insulating material placed between the plates of a capacitor that increases its capacitance by reducing the electric field.

Farad:

The unit of measurement for capacitance, defined as one coulomb per volt.

Impedance:

The total opposition that a circuit presents to alternating current, including both resistance and reactance.