Current sources and sinks are analysis formalisms which distinguish points, areas, or volumes through which
current enters or exits a system. While current sources or sinks are abstract elements used for analysis, generally they have physical counterparts in real-world applications; e.g. the
anode or
cathode in a
battery. In all cases, each of the opposing terms (source or sink) may refer to the same object, depending on the perspective of the observer and the
sign convention being used; there is no intrinsic difference between a source and a sink.