A capacitor is a device that stores charge. It consists of an insulating dielectric material sandwiched between two metal electrodes. When a voltage is applied across the metal electrodes, charge is stored on the electrodes. Capacitors are widely used in circuits for DC isolation, coupling, bypassing, filtering, tuning, and energy storage. Selection of Capacitor Types: Electrolytic capacitors are ideal for power supply filtering and decoupling circuits. Ceramic dielectric and monolithic capacitors are suitable for high-frequency and high-voltage circuits. CBB, ceramic, and organic film capacitors are recommended for resonant circuits. Polyester, monolithic, and electrolytic capacitors can be used for DC isolation. Tantalum (niobium) electrolytic capacitors offer stable and reliable performance but are expensive, making them suitable for circuits with high requirements, such as timing and delay.