What is the difference between AC and DC currents?

Answer 1

The difference between AC and DC currents is in terms of current flow. In the case of AC current, current can flow from one point to another and back again. It is reversible. But in the case of DC current, current can only flow in one single direction or from one point to another and not back again.

Answer 2

In DC, the electrons flow steadily in a single direction, or "forward." In AC, electrons keep switching directions, sometimes going "forwards" and then going "backwards." The power that comes from wall outlets is AC.

Answer 3

The Letters.

Sensible answer:

Current is actually the passage of electrons from one terminal to another.

The electrons actually travel FROM -ve TO +ve.

Convention, however, has it that the current travels FROM +ve TO -ve.

In a DC system (directional current or direct current) the positive (or +ve) terminal is always at a higher voltage than the negative (or-ve) terminal.

In this system, the current travels in one direction only.

It can be seen that the current always travels in one direction and is therefore directional (or direct).

In an AC system the voltage changes phase.

That is first +ve on one pole and -ve on the other, it then swaps to -ve and +ve, and then swaps back again.

Thus the voltage, when measured on either of the contacts, is observed to alternate.

Since the current flows from high (+ve) to low (-ve) conventionally, it is seen to change direction when the voltage polarity changes. If you would flowing left to right and then right to left and back again.

So the current is observed to alternate in direction hence the name AC alternating current!