Question

What affects the inductance of a coil?

Answer 1

Factors affecting inductance of a coil

1. When a current flows in a circuit it produces a magnetic field in the surrounding space and hence there will be a magnetic flux linked with the circuit.
2. If the current through the circuit varies with time the flux linked with the circuit also varies with time and gives rise to an induced emf in the circuit.
3. This phenomenon is known as self-inductance.
4. According to Lenz's law, the induced emf opposes the change in current in the circuit.
5. For this reason, it is called a back emf.
6. Self-inductance plays somewhat the same role in electrical circuits that mass plays in mechanical systems.
7. Thus, the self-inductance of a circuit is a measure of its inertia to changes in current.
8. If the circuit is in a nonferromagnetic medium the flux linked with it will be proportional to the current $I$ in the circuit.
9. $L=\frac{N^2\mu A}{I}[L=induc\tan ceofcoil,N=numberofturns,\mu =Permeability,A=area,I=Length]$
10. The number of wire turns in the coil. The inductance increases with the number of turns of wire in the coil. Less inductance is produced by a coil with fewer wire turns. For a given quantity of coil current, more wire coils suggest a stronger magnetic field force.
11. Coil area: The inductance increases with the coil area. Inductance decreases with decreasing coil area. For a given field force, a larger coil area offers less resistance to the development of magnetic field flux.
12. Core material: The inductance increases with increasing magnetic permeability of the core around which the coil is wound; it decreases with decreasing magnetic permeability of the core.
13. Coil length: The inductance decreases as the coil's length increases. The coil's inductance increases with its length.