| 摘要 |
PURPOSE:To inhibit the actuation of a receiver when a fault arises, by detecting the fault and then stopping the operation of a horizontal driving circuit in case the secondary winding of a flyback transformer has a short circuit. CONSTITUTION:When a short circuit arises to one turn of the secondary winding of a pulse transformer 5, the current of a power supply line 7 increases. Then the voltage drop increases for resistances 8a and 8b to turn on a transistor (TR) 10, and a current flows to resistances 11 and 12. Thus the voltage drops of the resistances 11 and 12 exceed the level of Zener voltage of a Zener diode 13. As a result, the diode 13 turns on together with a diode 16 and a thyristor 17. Then the terminal voltage of a resistance 19 rises up to turn on a TR 22, and therefore the output of a horizontal output TR 3 does not exist any more. Thus no input is applied to a flyback transformer 4 and the transformer 5 neither. |
