How Does the Horizontal Deflection Circuit Work?
Although there are many variations, the basic operation of the horizontal deflection/high voltage power supplies in most TVs, monitors, and other CRT displays is very similar. Since the flyback is constructed with an air gap in the core, it behaves more like an inductor than a transformer as far as the primary drive is concerned. There are scan rectifiers and the coupling factor with the primary is decent. But they make no use of the stored magnetic energy, they load the primary directly during the scan part. They do not cause an increase of the stored magnetic energy so a heavy load is not a problem. The flyback rectifiers (especially the EHT) draw from the stored magnetic energy. When the secondary load increases, also the magnetisation current will increase. Ultimately this will cause saturation of the ferrite core. Excess beam current is a common cause for this and should be avoided by the beam current limiter. The advantage of a flyback rectifier is that it provides 7 times more v
