Question

Is inductance AC or DC?

Answer 1

Inductance itself is not AC or DC; it's a property of a circuit component (an inductor) that opposes changes in current, whether the current is alternating (AC) or direct (DC). However, the behavior of an inductor depends on the type of current:

1. In DC Circuits: When a constant DC current flows through an inductor, the inductor initially opposes the change in current (when the circuit is first powered on). But once the current reaches a steady state, the inductor acts like a short circuit (with very low resistance), and there is no opposition to the DC current.
   

1. In AC Circuits: In an AC circuit, the current constantly changes direction and magnitude. Inductance opposes changes in the current more effectively because the inductor creates a back EMF (electromotive force) that resists the change in current. The opposition to current flow in an AC circuit is called reactance, and it increases with frequency.
   

In summary:

1. DC: Initially, inductors resist the change in current, but eventually, they allow DC to pass freely once steady state is reached.
   

1. AC: Inductors provide opposition to the AC current, and the opposition (called reactance) depends on the frequency of the AC signal.