| 摘要 |
PURPOSE:To simply protect a circuit at an abnormal state, by connecting 1st and 2nd resistors in series, inserting them between an input terminal voltage of a flyback transformer and earth, and providing a diode so as to be a cathode at the midpoint side, thereby detecting the reduction in an input terminal voltage. CONSTITUTION:A +B1 voltage is inputted to one terminal of a flyback transformer via a current limit resistor 14. A caption +B2 is an output voltage. The voltage +B1 is divided into optional voltages by divider resistors 15, 16 and the voltage at the connecting point is connected to a base of a transistor(TR) 18 via the diode 17. When the input voltage +B1 is decreased at the short- circuit test of a flyback terminal, the midpoint voltage of the divider resistors 15, 16 is also decreased. Thus, the diode 17 and the TR 18 are conductive, resulting that the shut-down control terminal of the deflection circuit 19 goes to a high level. Then the horizontal pulse output terminal of the deflection circuit 19 goes to a low level, the horizontal drive TR 20 is interrupted and the receiver is shut down. |
