In electronics, a center tap is a wire that is connected to a point half way along one of the windings of a transformer , inductor or a resistor. Center taps are sometimes used on inductors for the coupling of signals, although most tappings are not at the centre but usually near one end. In the case of resistors, tapping is usually done only with potentiometers, and center tapping is just a special case of normal operation of these devices.