Question

Is self-induction greater in AC or DC?

Answer 1

Self-induction (or inductance) is greater in AC (alternating current) than in DC (direct current).

Here’s why:

1. In DC circuits, once the current starts flowing, it becomes constant after a short time. The rate of change of current is zero after the initial switch-on period, which means the inductance doesn't play much of a role once the current stabilizes. In a DC circuit, the inductor only resists changes in current at the moment when the current is first applied or when it is suddenly interrupted.
   

1. In AC circuits, the current constantly changes direction and magnitude. This continuous change causes the magnetic field around the inductor to change constantly, inducing an electromotive force (EMF) that opposes the change in current. Since the current is always changing, the inductor is always "working," and the self-induction is more noticeable.
   

Therefore, self-induction is more significant in AC circuits because of the continuous variation in current, which constantly induces opposing voltages.