The variable inductor having an adjustable ferrite core is known as slug tuned inductor. The value of inductance increases or decreases respectively, due to the movement of a ferrite core into or out of the coil winding.
- The basic construction of a slug tuned inductor is shown in fig.
- This construction is similar to the fixed ferrite core inductors, but the core is adjustable.
- The value of inductance increases, when the slug is moved into the coil winding and decreases the resonant frequency of the tuned circuit.
- When the slug is moved out of the coil winding, the inductance decrease and the resonant frequency of the tuned circuit increases.
- The value of inductance can be varied by using movable core which can be moved up or down by using screw driver.