Voltage Sources vs. Current Sources

Voltage Source

• A voltage source maintains a fixed supply voltage to an electrical circuit - independent of the circuit load resistance and the applied current.

Current Source

• A current source maintains a fixed supply current through an electric circuit - independent of the circuit load resistance and applied voltage.

Note that real voltage and current sources have limits to the voltage/currents they can provide. A voltage source "prefer" open circuits (no connection between the poles) and current sources "prefer" closed circuits (short cuts).