Kapasitor

Kapasitor, in electronics often referred to as a capacitor, is a passive component that stores electrical energy in an electric field created between two conductive plates separated by a dielectric. The device releases the stored energy when required by the circuit. Kapasitors are used to store charge, filter signals, stabilize voltage, and couple or decouple stages.

A kapasitor consists of two conductive plates with a dielectric insulator between them. The capacitance, a measure of how much charge can be stored per volt, depends on the plate area, the distance between plates, and the dielectric material: C = ε0 εr A / d. The energy stored at voltage V is E = 1/2 C V^2. Real devices also have parasitic properties such as equivalent series resistance (ESR) and equivalent series inductance (ESL) that affect performance at higher frequencies.

Common types include ceramic, film, electrolytic, tantalum, mica, and paper capacitors. Ceramic capacitors are often small and inexpensive; film types offer stability and low loss; electrolytic and tantalum types provide high capacitance in compact form but may be polarized and have higher leakage. Capacitors are specified by capacitance value, voltage rating, tolerance, leakage current, and, for some types, temperature and impedance characteristics.

Applications span filtering (smoothing power supplies, removing noise), timing and waveform shaping, energy storage in power electronics, and DC coupling/decoupling between circuit stages. Design considerations include dielectric type, voltage rating, temperature coefficient, tolerance, size, and reliability. Failures can result from overvoltage, dielectric breakdown, aging, or mechanical stress.