JPS6449476A - Horizontal output circuit - Google Patents

Abstract

PURPOSE:To prevent exerting a basic influence on a screen by maintaining a high output voltage, a horizontal amplitude and a fly-back line rate constant and, simultaneously, preventing a fly-back transformer from being magnetically saturated at the time of switching a horizontal frequency. CONSTITUTION:A frequency fractioning circuit 5 fractions the degree of the horizontal frequency of a voltage pulse to be added from a horizontal driving circuit 1 to a horizontal output transistor 2 and sends the fractioning signal to a switch driving means 6. The means 6 is composed of a relay circuit 30, the circuit 30 moves respective switches 14, 15 and 18 in required directions corresponding to the fractioning signal and the circuit 30 switches resonance capacitor circuits 8 and 10, sigmaidal correcting capacitor circuits 12 and 13 and power circuits 20 and 21 corresponding to the horizontal frequency. Here, the capacities of the resonance capacitors 8 and 10, the output voltages of the power sources 20 and 21 and the position of a intermediate tap 23 of a low pressure coil 22 are set so as to meet the conditions of high output voltage constancy of a fly-back transformer 16, the conditions of fly-back line rate constancy of a fly-back pulse, the condition of a horizontal deflection amplitude constancy and the conditions on which a core 24 of the transformer 16 is not magnetically saturated.