Current Flow

Now lets look at how current flows in a circuit.

Schematic Symbol	Actual Image

Current flows from the + (positive) terminal of a battery, through whatever is connected to it, and to the - (negative) terminal of the battery. Remember that we frequently call the negative terminal of the battery ground.

It is not possible to have current unless you have a closed circuit. As soon as the circuit is opened, the current stops flowing. However, in an open circuit the voltage remains present.

Schematic Symbol	Actual Image

In the picture above the circuit is open so there is no current flowing. However voltage is still present in the circuit.

The Voltage to Water Analogy

A common way to think about voltage and current is to think about water in a lake. Voltage is like the amount of water present, whether it is moving or not. Current is the amount of water flowing.

The lake is a like battery with a large voltage. The river flowing out is current.

When you have a large body of water, you have the potential of having a large current. Similarly, when you have a large voltage you have the potential of having a large current.