How a Capacitor Works

An electrical capacitor is made of two small conductive plates separated by what is called a dielectric, which effectively insulates the two plates and stops any current from being transferred between the plates themselves. Instead, the two plates are connected through a circuit. When the circuit is taken out, the plates store the electrical current because it can't flow between the plates.

The way a capacitor works is like a water storage tank with a shut-off valve if it gets too full. As electrical current enters the capacitor, the capacitor lets it pass through unaffected. However, the more current flows into the capacitor, the quicker it "fills." This then triggers the capacitor's shut-off mechanism, preventing electrical current from exiting and redirecting the flow to a grounding current.



Capacitor Coding:

How a Capacitor works in a Fan
One use is to provide phase shift in one of the motor's windings. This is either called a "capacitor start" motor, or a "capacitor start / capacitor run" motor.
Since a motor must have a rotating magnetic field to produce rotation of the rotor, the capacitor, produces a phase shift in one winding so it lags and produces a lagging field compared to the other winding. This time lag will then cause a rotating force or torque on the rotor...thus rotating the rotor and making a motor.

Posted in: Electronics