Reactive time bases

The use of wide-angle large screen cathode-ray tubes for television purposes has led to the necessity for high-efficiency line time bases. The paper describes the various methods which can be employed to recover the energy present on the deflection field at the end of the scan, either to be returned to the H.T. rail or alternatively to provide a voltage boost to supply the driver stage. The design of the voltage booster circuit either with an auto-transformer, or with a multi-wound transformer, is discussed in detail with reference to efficiency, linearity and convenient operation from H.T. supplies of the order of 200 V. Particular reference is made to the design problems of the transformer and mention is also made of a direct-drive system whereby the circuit can operate directly on to high-impedance deflection coils.