| 摘要 |
PURPOSE:To keep the input voltage to be applied to a regulator within a fixed range by providing a voltage comparator and a tap selecting circuit to a power supply circuit and selecting taps having different numbers of turns at the primary or secondary side of a power supply transformer as the power supply voltage has a big shift. CONSTITUTION:A voltage comparator 5 decides whether the secondary voltage of a power supply transformer T is set within a prescribed range compared with the set value of the secondary voltage. The tap of a tap selecting circuit 1 is switched in accordance with the result of decision of the comparator 5. As a result, the tap is selected so that the voltage of the secondary side is set within a fixed range. A CPU controls the comparator 5 and the load. |
