Air core inductor is an electrical component used to store the energy resulting from current passing through it in a magnetic field.
Constructions:

- The basic construction of air core inductor it consist of coils having number of turns of wire wound on a former made of ordinary cardboard.
 - The plastic or ceramics may be used for a former as an insulating material.
 - Since there is nothing but air inside of former, the inductor is known as air core inductor.
 - The gap inside a plastic or paper former acts as a core. Thus air acts as a core.
 - The magnetic wire wound on the former from the coil of the inductor.
 
Requirement of air core coil
The main requirements of air core coils are as given below,
- Stability of inductance.
 - Low self capacitance.
 - Reasonable size and cost.
 - Low temperature coefficient.
 - High ratio of inductive reactance to effective loss resistance at operating frequency.
 
