INDUCTORS

1. Inductors is the ability of a conductor to produce induced voltage when the current varies.

2. A steady direct current is not affected by inductance.

 

SELF-INDUCTANCE (L) 

The ability of a conductor to induce voltage in itself when the current changes is its ‘self-inductance’. Its unit is Henry (H).


MUTUAL INDUCTANCE (Lm) 

The ability of a conductor to induce voltage in a separate circuit with which it is magnetically linked is called ‘mutual inductance’. Its unit is Henry (H).


 TYPES OF CORES

1. Air Core

a) In this type air acts as core.

b) Conductor is wound on a hollow tube. There is loss of magnetic flux.

c) Air core coils for RF application are called chokes which have L values in mH or µH.

 

2. Iron Core

a) Iron is placed in a former. Magnetic flux leakage is negligible as iron a ferromagnetic material.

b) For audio frequencies and power frequency (50 Hz ) laminated iron core used.

 

3. Ferrites Core

a) Ferrites are synthetic ceramic materials. As these are insulators, a ferrite core can be used for high frequencies with minimum eddy currents losses.

b) This core is usually a slug that can move in or out of the coil to vary L.