| 摘要 |
PURPOSE:To improve a regulation by switching the secondary winding voltage of a power source transformer by the rectified output voltage. CONSTITUTION:A power source circuit applies the primary AC voltage to input terminals 1, 2 of a power transformer 3, full-wave rectifies the voltage generated from the secondary winding by rectifying diodes 4-7, and smoothes it by electrolytic condensers 8, 9. This voltage is applied through power amplifier transistors 11, 12 to a load 10. The circuit has a voltage detector 15, a switching drive circuit 16, and voltage changeover switches 17, 17', and terminals (a), (b) for producing high and low voltages are provided in the secondary winding of the transformer 3. Thus, if the rectified output voltage detected by the detector 15 drops lower than the low reference voltage Vm, the drive circuit 16 connects the switches 17, 17' with a high voltage side (b), and if it rises from a high reference voltage V1, it connects to the low voltage side (a), thereby suppressing the voltage varying width. |
