Electric current

From Simple English Wikipedia, the free encyclopedia

Current is the flow of electric charge. The equation of current is:

I = \frac{\Delta Q}{\Delta t}
where
I is the current flowing
ΔQ is the change in electric charge
Δt is the change in time

The SI unit of electric current is ampere (A). This is equal to one coulomb of charge in one second. Current can be found in wires, batteries, and lightning.

[edit] Conventional current

Conventional current is the flow of positive charge. It is a stream of positive charges moving in one direction and flow in the opposite direction of electron. It goes from the positive to negative side of the starting position. But this is wrong because positive charges do not move in solid metals. It is really electron flow happening in a circuit made of solid metals.

[edit] Electron flow

Electron flow is a stream of negative charges moving in the opposite direction of conventional current, from negative to positive. A cathode ray is an example of electron flow. It is a stream of electrons in a vacuum tube.

[edit] Current in circuits

When current is flowing in a wire circuit, it accelerates when there is no resistance in the circuit. Resistors are used to increase resistance in the circuit so it slows down the current. The relationship between resistance, current, and voltage (another part of the circuit) is shown by Ohm's law.