Actually what is Alternating Current?

Fig: Alternating Current

When we plug some electrical equipment to the Wall Socket, what is happening?
What the Power Houses are selling to us?
Are they selling electrons or just Energy?

The type of current that is provided by generators is called alternating current(ac).

The electrons in the circuit do not move in any direction but simply vibrate about a fixed point. The energy from the outlet causes the electrons, already in the circuit or lamp filament, to vibrate.

So in general, the Power Stations sell energy to us not electrons. We supply the electrons.

When we buy a piece of wire from the Hardware store what we actually by is the supply of electrons that will be placed in our circuit. "Wire" is another name for electron source. 

Some people think that the electrons are travelling from the Power house to our House and then to the equipment. Actually, this is not true.

Look at the animation on the right and notice how the electrons do not move in any particular direction but move to and fro about a fixed point.

(Courtesy: www.dynamicscience.com)