AC adaptor VS DC adaptor

When purchasing a Power Supply for your electrical device, there are two general types: AC adaptors and DC adaptors. While they may look very similar and have similar looking inputs and outputs, their functions are very different.

How an AC Adaptor Works

In short, an ac dc adapter converts the electric currents received by the electrical outlet into a typically lower alternating current that an electronic device can use.
Inside the power adaptor are two wire windings that wrap around a single iron core. The first of the windings receives the 120-volt alternating current delivered to the electrical outlet, and creates an electric field in the iron core. The second wire winding turns the newly created electric field into a smaller alternating electric current. The measure of the resulting alternating current is dependent upon the number of coils in the second wire winding in relation to the number in the first winding. If the second winding is half of the first winding, the alternating current will measure half of what it did when it entered the AC adaptor. Therefore, if there were 100 coils on the first winding, the second winding will have only 50 coils.

AC/DC: The Two Electric Currents

The abbreviation, AC, stands for alternating current and is used to describe the electrical currents utilized to deliver power from power plants to homes and businesses. When graphed, these alternating currents are shown as waves that go up and down; this is because these currents do not flow constantly in one direction, but alternate directions, flowing forward and backward.