What are some examples of capacitors used in circuits?

They serve as energy storage devices that release stored energy as needed.

Case1: Camera flash An array of capacitors can store enough energy and release it very quickly across the bulb filament. A camera flash needs a lot of energy in a short amount of time to produce a bright enough flash. A battery cannot produce a bright enough flash.

Case 2: Computer emergency shutdown: In the event of a power outage, a capacitor array can be utilized to limit damage and give a computer enough time to save important files. The capacitors charge automatically when the computer is powered on, and in the event of a power outage, they will automatically discharge through the circuitry, giving the computer a brief window of time to save important files, etc.

Case 3: AC to DC conversion This is not strictly an energy storage facility. The rectifier is the essential component of the AC to DC conversion. The rectifier's output is not smooth; instead, it has the peaks of the sinusoidal AC signal. To smooth the signal, capacitors in the circuit can be charged at the peaks and then discharged during the gaps. In terms of energy storage, the capacitors store part of the peak energy and release it during the gap, resulting in an output energy that is roughly constant.

A sudden current draw can lower the voltage to other devices sharing that power line. This is demonstrated by the fact that most capacitors in a device like a cellphone are decoupling capacitors, also called bypass capacitors. The chips are essentially switches, so they turn on and off various currents. For example, when the air conditioning turns on or when Dr. Frankenstein throws the switch, the lights dim momentarily.

Because digital logic chips and other chips cannot function properly if their power line voltage falls below a certain level, each chip has one or more decoupling capacitors next to its power pin(s). The purpose of the coupling capacitor is to provide power to the local chip when another chip draws a lot of current, lowering the voltage; in other words, it serves to decouple the power to the local chip from the power to the others.

Playing hot air Jenga with electronics is a lot of fun, and a good strategy is to start with the bypass caps, which can usually be removed all or almost all of the way without causing any problems.

Capacitors are also used as coupling capacitors, where the purpose is to eliminate any DC component from a signal before sending it to the next stage. Usually, a signal, for example, is sent to the base of a transistor, which requires the right DC bias to function. Any additional DC from the signal will cause this bias to shift, which can lead to issues.

Examples of capacitors used in circuits include ceramic capacitors, electrolytic capacitors, tantalum capacitors, and variable capacitors.