Question

Do inductors block AC or DC?

Answer 1

Inductors don’t completely "block" AC or DC, but they react differently to each:

1. DC (Direct Current): When a DC current is applied to an inductor, it resists the change in current initially (because of its inductance), but once the current reaches a steady value, the inductor behaves like a simple piece of wire with very little resistance. So, inductors allow DC current to pass through after the initial surge.
   

1. AC (Alternating Current): In AC circuits, the current is constantly changing direction. An inductor resists changes in current more strongly as the frequency of the AC increases. This happens because the changing current creates a changing magnetic field around the inductor, which in turn creates a voltage that opposes the current (known as inductive reactance). The higher the frequency of the AC, the more the inductor "resists" it, effectively reducing the current.
   

So, inductors "block" AC more than DC, especially at higher frequencies, but they don't completely block either one. The resistance to AC is called inductive reactance, and it depends on the frequency of the AC signal.