- Air ganged capacitor consists of two sets of aluminiums plates separated from each other by air. These metal pates may be rotary or concentric type. The rotary type configuration has a rotor and a stator.
- The concentric type configuration has two cups of aluminum.
- The concentric type variable capacitor consists of two cups of aluminium, one moving in other.
- The movement is actuated by a threshold screw.
- One set of the plates in fixed, while the other set is connected to a shaft and can be rotated.
- The fixed set of plates is insulated from the body of a capacitor on which it is mounted.
- The set of moving aluminium plates with the help of a suitable knob connected to a rotating shaft.
- As the plates are moved in and out of the fixed plates, the capacitance value varies.
- The capacitance is minimum, when the moving plates are completely out and it is maximum, when the moving plates are completely in.
- The fixed plates are called stators, which are normally made of brass, copper or aluminium.
- The cadmium plated steel is used for the frames in low cost capacitors.
- The outer set of plates is called rotors.
- They get interleaved with stators, when the shaft is rotated. Sometimes, two or more such capacitors are operated by a single shaft.
