Capacitance is measured in farads (F), as the farad is a very large unit, capacitors are most commonly used in much smaller values such as microfarads (mF or �F)

A capacitor is a discrete component that can store an electrical charge. Similar to a rechargeable battery, it is "charged" when the mains power is turned on. This charge is used in pumps and some fans to provide a "boost" on initial start up, without this the motor may not have enough torque to over come the inertia of its impeller. Without a load all capacitors store a charge for a long time after the mains power has been isolated, any conductor that touches both terminals of the capacitor will cause it to discharge.

To measure capacitance with a multimeter the capacitor must first be discharged and at least one side removed from its circuit. The meter can then be conected to the capacitor, one probe on each terminal, the meter will then show the value of the capacitor.