Inductance

Self-inductance, mutual inductance, inductors, and energy storage in magnetic fields.

General idea of the topic

This block studies how a circuit opposes changes in current through self-induction and how two nearby circuits couple mutually, transferring energy via mutual inductance.

It analyses the energy stored in the inductor's magnetic field, the time constant in RL circuits and the role of inductance as a reactive element that stores rather than dissipates energy.

What you will truly understand

• How to define and calculate the self-inductance of solenoids and coils.
• How the self-induced EMF opposes changes in current according to Lenz's law.
• How to calculate the energy stored in an inductor.
• How to model transients in RL circuits with time constant.

Recommended learning route

1. Self-inductance and calculation for basic geometries.
2. Energy stored in the magnetic field.
3. RL circuits and transient response.

Physical criterion you must acquire

Treat the inductor as an element that stores energy in the field, not as a variable resistance. Verify the coherence of the self-induced EMF sign with the current variation.

Connection with real problems

Power supply filters, choke coils, transformers, ignition circuits and surge protection.

Final goal of the topic

Solve inductance problems with energy calculation, time constant and sign coherence.