| 摘要 |
PURPOSE:To obtain a stable oscillation by stopping a base current to be energized when the collector current of an oscillation transistor becomes almost zero. CONSTITUTION:When a power source is turned ON, a weak base current is flowed through a resistor 5 to oscillation transistors 8, 9 to cause an oscillator to oscillate. A voltage induced at the tertiary winding 13 is rectified by a rectifier 15 to charge a capacitor 16. A photoreceptor 20 of a photocoupler is connected with the base of a synchronous transistor 18, synchronized and conducted with the collector currents of the transistors 8, 9. The collector currents of the transistors 8, 9 become zero when a commercial power source 1 crosses at zero, a transistor 18 is turned OFF at this time to interrupt the base current. |
