Electrical Engineering Fundamentals/Current Sources

An independent current source has a constant current that is completely independent of the voltage across the source. Like the independent voltage source the current source is at best a reasonable approximation for a physical element. It is a common mistake that students think the voltage across a current source is zero and that is false. There is a voltage across current sources. This voltage is, for an ideal current source, always equal to, the current output (amperes) times the load resistance (ohms).