Capacitor Types and Their Uses

Choosing the right capacitor.

Ceramic capacitors are small, cheap and good at high frequency. Film capacitors are stable and accurate. Electrolytic capacitors give large capacitance in a small size but are polarised, so connecting them backwards can damage them.

Typical jobs are smoothing the output of a rectifier, decoupling the supply near a chip, coupling signals between stages, setting timing and building filters. Large capacitors can hold dangerous charge, so discharge them safely before touching a board.

• Always check polarity on electrolytics.
• Voltage rating must exceed the circuit voltage.
• Decoupling parts sit close to the chip they serve.

Browse all 50 physics and electronics pages  |  Back to the course index