Mutual inductance. When a changing current in one circuit causes a changing magnetic flux in a second circuit, an emf is induced in the second circuit. and , – mutual inductance, – number of turns of coil of the first circuit, – average magnetic flux through each turn of coil 1.
Self-inductance. A changing current in any circuit causes a self-induced emf , – depends on the geometry of the circuit and the material surrounding it.
Magnetic field energy. An inductor with inductance carrying current has energy associated with the inductor’s magnetic field: . Magnetic energy density: .
R-L circuits. In an R-L circuit the growth and decay of current are exponential with time constant .
L-C circuits. An L-C circuit undergoes electrical oscillations with an angular frequency .
L-R-C circuits. The frequency of damped oscillations .