Self-inductance or simply inductance of a coil is defined as the flux linkage of the coil when 1A current flows through it.
When the current i changes with time, an emf is induced in it. From Faraday’s law of electromagnetic induction, this self-induced emf is given by
The negative sign in the above equation means that the self-induced emf always opposes the change in current with respect to time. If \(\frac{di}{dl}\) = 1 AS-1, then L= -ε. Inductance of a coil is also defined as the opposing emf induced in the coil when the rate of change of current through the coil is 1 AS-1 .
