| 摘要 |
PURPOSE:To protect a driving transistor (TR) from a pulse voltage at the turn- on of a power switch, by connecting an output of a rectifying and smoothing circuit to a power supply voltage via a reverse current preventing diode and connecting a resistor having a low resistance in parallel with this diode. CONSTITUTION:In closing a power switch, a +B1 voltage line supplies power to a +B2 line via a high resistance 13. A resistor 14 having a low resistance 14 and a capacitor 15 are connected in parallel with the resistance 13 and the charging current of the capacitor 15 supplies sufficient power to a driving TR2 instantly. Through the operation of the TR2, a horizontal output TR4 is operated and a horizontal deflection current flows to a horizontal deflection coil 7 and a high voltage EHT applied to the anode of a CRT is picked up at a flyback transformer 8. A pulse voltage is generated across a resistor 16 at the secondary winding of the transformer 8, the voltage is rectified and smoothed at a rectifier diode 9 and a smoothing capacitor 10 to obtain a voltage +B2 in place of a voltage from a circuit consisting of the resistors 13, 14 and the capacitor 15 via an inversion preventing diode 11. |
