Auto scan horizontal deflection apparatus

摘要

An auto scan horizontal deflection apparatus comprising a voltage detecting circuit as an amplitude detecting winding arranged at a secondary side of a choke transformer and detects amplitude of a flyback pulse. A frequency discriminating circuit (frequency/voltage converting circuit) discriminates frequency of horizontal synchronizing signal, and a control signal generating circuit (adding circuit) generates a control signal controlling the power source voltage of a variable power circuit supplying a power source voltage to a horizontal output circuit through a primary winding of the choke transformer on the basis of the outputs of both circuits. It becomes possible for the apparatus to keep horizontal deflection width constant regardless of the horizontal deflection frequency without using a conventionally-used detection resistance whose electric power loss is large, thereby decreasing electric power loss and keeping the horizontal amplitude almost constant even when the horizontal deflection frequency is changed.