| 摘要 |
PURPOSE:To improve the reliability of an automatic converter by employing a DC voltage rectified from an AC voltage and stopping the oscillation of a transistor when the DC voltage decreases, thereby eliminating unstable voltage. CONSTITUTION:An AC power source 5 is rectified and smoothed by diodes 1- 4, thereby forming a self-excited converter which turns ON and OFF the DC voltage by a switching transistor 8. This output is rectified and smoothed at 11, 12 through the secondary coil of the transformer 10. The partial voltage of the power source 5 is smoothed through a diode 13, resistors 14, 15 and a capacitor 16. Here, when the voltage of the power source 5 decreases, it is detected via resistors 18, 20, and transistors 17, 19 are conducted via the smoothed voltage. In this manner, the transistor 8 is turned instantaneously OFF, thereby avoiding the unstable operation of the oscillation. |
