Mutual inductance

Definition

Mutual inductance is the phenomenon where a change in the current in one coil induces a voltage in another coil that is magnetically coupled to it. It is quantified by the mutual inductance coefficient, which depends on factors like the number of turns in each coil and their relative positioning.

5 Must Know Facts For Your Next Test

1. The unit of mutual inductance is the Henry (H).
2. Mutual inductance can be positive or negative depending on the orientation of the coils.
3. Faraday's Law of Induction explains how a change in magnetic flux induces an electromotive force (EMF) in another coil.
4. The mutual inductance (M) between two coils is given by $M = \frac{N_2 \Phi_{21}}{I_1}$, where $N_2$ is the number of turns in the secondary coil, $\Phi_{21}$ is the magnetic flux through one turn of coil 2 due to current $I_1$ in coil 1.
5. Coupling coefficient (k) ranges from 0 to 1 and indicates how effectively two coils are magnetically coupled.

Review Questions

• What is mutual inductance and what factors does it depend on?
• How does Faraday's Law of Induction relate to mutual inductance?
• What is the significance of the coupling coefficient (k) in mutual inductance?

Related terms

Inductance:

A property of an electrical conductor that opposes a change in current, measured in Henrys (H).

Faraday’s Law of Induction: A law stating that a change in magnetic flux through a circuit induces an electromotive force (EMF) proportional to the rate of change.

Coupling Coefficient: A dimensionless parameter ($k$) ranging from 0 to 1 that measures how effectively two coils are magnetically coupled.