The rotor plates when moved into the slots of stator, they come close to form plates of a capacitor. The stator is a stationary part and rotor rotates by the movement of a movable shaft.

The constructional details of a tuning capacitor are shown in the following figure. They contain a stator, a rotor, a frame to support the stator and a mica capacitor. Tuning capacitors are popular type of variable capacitors. The main types of variable capacitors are Tuning capacitors and Trimmer capacitors.

There are many uses of these variable resistors such as for tuning in LC circuits of radio receivers, for impedance matching in antennas etc. The dotted line indicates that they are connected internally. A single shaft is used to rotate the variable ends of these capacitors which are combined as one. The ganged capacitor shown here is a combination of two capacitors connected together. These capacitors provide the capacitance values so as to vary between 10 to 500pF. Variable capacitors in general consists of interwoven sets of metallic plates in which one is fixed and the other is variable. Let us know something about the variable capacitors whose value alters when you vary, either electrically or mechanically. The fixed capacitors are the ones whose value is fixed at the time of manufacturing itself and the variable ones provide us with an option to vary the value of capacitance. The main classification is just like the above one. The classification is as shown in the following figure. The main classification is done according to fixed and variable capacitors. There are many types of capacitors depending upon their function, the dielectric material used, their shape etc.

Polyvaricon variable capacitor