A variable capacitor is a capacitor whose capacitance can be adjusted within a certain range. By changing the relative effective area between the pole pieces or the distance between the pieces, its capacitance will change accordingly. Usually used as a tuning capacitor in a radio receiving circuit.
A capacitor whose capacitance can be adjusted within a certain range is called a variable capacitors.
It is generally composed of two sets of pole pieces that are insulated from each other: a fixed set of pole pieces is called a fixed piece, and a movable set of pole pieces is called a moving piece. The moving plates of several variable capacitors can be combined on the same shaft to form a coaxial variable capacitor (commonly known as double, triple, etc.). Variable capacitors have a long handle, which can be adjusted by attaching a cable or dial. Variable capacitors are capacitors whose capacitance can be adjusted within a certain range. They are usually used as tuning capacitors in radio receiving circuits. Generally, it is widely used as tuning, compensation capacitor/correction capacitor in various tuning and oscillation circuits of radio (such as radio, TV) or NFC/RFID card readers.
The principle is generally that by changing the relative effective area or distance between the pole pieces, its capacitance changes accordingly.