with the impedance. A visual example of a source transformation can be seen in Figure 1. A brief proof of the theorem The transformation can be derived from the uniqueness theorem. In the present context, it implies that a black box with two terminals must have a unique well-defined relation between its voltage and current. It is readily to verify that the above transformation indeed gives the same V-I curve, and therefore the transformation is valid. See also Ohm's Law Thévenin's theorem Current source Voltage source Electrical impedance References Electrical engineering Electronic engineering Electrical circuits Electronic circuits Electronic design Circuit theorems