A capacitor is a passive electronic component that stores electrical energy in an electric field. It consists of two conductive plates separated by a dielectric or insulating material. When voltage is applied, positive charges accumulate on one plate and negative charges on the other, creating an electric field between them.
There are several types of capacitors, each designed for specific applications. Ceramic capacitors are small, stable, and low cost, commonly used in high-frequency circuits. Electrolytic capacitors offer high capacitance values but are polarized. Film capacitors provide precise values with low loss. Variable capacitors allow adjustable capacitance for tuning circuits.
The fundamental formula for capacitance is C equals Q over V, where C is capacitance in farads, Q is charge in coulombs, and V is voltage in volts. The energy stored in a capacitor is given by E equals one half C V squared. When capacitors are connected in parallel, their capacitances add directly. In series, the reciprocal of total capacitance equals the sum of reciprocals of individual capacitances.
Capacitors have numerous practical applications in electronics. In power supplies, they filter and smooth voltage ripples from AC to DC conversion. They are essential in timing circuits, controlling delays and frequencies in oscillators. Capacitors enable AC coupling by blocking DC while allowing AC signals to pass. They store energy for high-power applications like camera flashes and defibrillators. In motors, capacitors provide the initial phase shift needed for starting.
To summarize what we have learned about capacitors: They are passive components that store electrical energy in electric fields between two conductive plates separated by dielectric material. Various types exist for different applications, from ceramic to electrolytic capacitors. The fundamental relationships are capacitance equals charge over voltage, and stored energy equals one half capacitance times voltage squared. Capacitors are essential in modern electronics for power filtering, timing circuits, and energy storage applications.