Electrons flow in the direction opposite to the flow of current

[debojit das]

Its said that electrons flow in the direction opposite to the flow of current;then why does electron never get vanished when we switch on a fan and current flows from switch board to fan?

 

[collinsmark]

Its said that electrons flow in the direction opposite to the flow of current;then why does electron never get vanished when we switch on a fan and current flows from switch board to fan?

There's not only current traveling to the fan, but there is the same amount of current traveling away from the fan. Electric current always travels in a loop; with batteries, wires, fans, natural-gas burning power plants, etc., forming the different parts of the loop. That's why the fan turns on when you hit the switch, because you complete the loop. Breaking the loop (by opening the switch) turns the fan off.

That's why there are two wires in the fan's power cord -- at any instant in time, current is flowing in a given direction in one wire, and the opposite direction in the other wire. When you plug the fan cord into the wall, the two terminals make connections with other parts of the loop.

We have Benjamin Franklin to thank for the fact that electrons travel in the opposite direction as the current. He defined the convention of positive vs. negative charge, thus corresponding current flow. The decision was rather arbitrary at the time. But we can't blame him; the convention was made long before electrons were even discovered.

 

[DavidSullivan]

Regarding the direction of the current: a current can be created using positive or negative particles. By historical convention the direction of current is determined by the movement of positive charges. Because electricity is the movement of (negative) electrons, the current "flow" is opposite the movement of the electrons.

-David