Do Capacitors Release Relative Power or Actual Power?

About Capacitors

• A capacitor is similar to a battery insofar as it has the ability to store electricity and release it when required; however, at this point the similarity ends. There is no chemical reaction involved. The amount of electricity it stores is small; it charges and then releases electrical energy in a matter of milliseconds. A capacitor consists of two metal plates separated by a nonconductive material; its technical term is a dielectric, and is a form of insulator.

How a Capacitor Works

• Electricity flows through the wire from the power source to one of the plates in the capacitor, but at this point the electricity stops flowing, as it can̵7;t get past the dielectric. Electricity builds up in the metal plate until the voltage reaches a certain level. The dielectric can no longer insulate the electricity, so it discharges through the dielectric into the other plate in the capacitor and continues around the circuit. The type of plates used and the material that forms the dielectric determine how much voltage is stored before it is released.

Actual Power

• Actual or true power that flows through an electrical circuit is relative to the electrical energy produced by the power source. The electricity flowing through the circuit remains constant while the power source is turned on. It is measured in watts, and is a combination of voltage multiplied by amperes. For example, a battery producing 12 volts and 20 amperes is equal to 240 watts. If you introduce a capacitor into a circuit, it temporarily halts the flow of electricity; therefore, it is no longer actual power.

Relative Power

• A capacitor releases relative, not actual power. As mentioned previously, the flow of electrical energy is stopped by the dielectric between the two plates in the capacitor. Once the electrical energy reaches a certain level, it effectively jumps from one plate to the other as a single impulse. The flow then stops again until the plate releases another burst of energy. The electricity produced in pulses from the capacitor is called relative power.