Color television
The transformer can be equipped with extra windings whose sole purpose is to have a relatively large voltage pulse induced in them when the magnetic field collapses as the input switch is turned off. There is considerable energy stored in the magnetic field and coupling it out via extra windings helps it to collapse quickly, and avoids the voltage flash over that might otherwise occur. The pulse train coming from the flyback transformer windings is converted to direct current by a simple half wave rectifier. There is no point in using a full wave design as there are no corresponding pulses of opposite polarity. One turn of a winding often produces pulses of several volts. In older television designs, the transformer produced the required high voltage for the CRT accelerating voltage directly with the output rectified by a simple rectifier. In more modern designs, the rectifier is replaced by a voltage multiplier. Color television sets also have to use a regulator to control the high voltage. The earliest sets used a shunt vacuum tube regulator, but the introduction of solid state sets employed a simpler voltage dependent resistor. The rectified voltage is then used to supply the final anode of the cathode ray tube.