Sources

Electrical sources provide electrical energy with which something can be moved, illuminated or heated in electrical loads, for example. The German term "Verbraucher" (consumer) for a load is misleading, because energy is never consumed, only ever converted. So electrical sources carry electrical energy and provide electrical power so that this energy can be taken from the source and converted into another form.

To do this, most sources provide either a constant voltage or a constant current.