Virtually every electronic device in widespread use contains some form of capacitor. Used to store electricity, capacitors often help computers avoid losing their memory when the batteries are being recharged. Other devices, such as amplifiers for car stereos, contain capacitors that store energy until it is needed by the amplifier. Motion detectors use capacitors to help achieve the proper timing of the unit’s circuits.
Devices called power conditioners use capacitors to help power sources deliver consistent energy levels. Power conditioners are used in a variety of applications, especially audio systems. Amplifiers and audio systems also use capacitors to filter the range of frequencies passing through the system. When used in this manner, the capacitors create equalizers and various types of filters. Capacitors are often used in circuit boards to reduce the amount of noise that passes through the device.
Because capacitors store energy, some scientists are investigating ways that they can be used as batteries. Capacitors are already used in uninterruptable power supplies to help prevent computer networks and other devices from losing power during power outages.
Capacitors can also be used as sensing devices. Because they react to changes in humidity and other factors, capacitors can be used to ensure a device is working properly.