| 摘要 |
PURPOSE:To improve the efficiency of a power source by varying the base current of a transistor which turns ON or OFF at the output to be supplied to a load corresponding to the variation in the load. CONSTITUTION: A selector 7 closes a switch SW1 when a load 2 is started, and opens it at steady time. When the switch SW1 is ON, the base current of a transistor TR2 is determined by a resistance value due to the parallel connection of resistors R3, R6, thereby obtaining a large load current corresponding thereto. When the switch SW1 is OFF, the base current of the transistor TR2 becomes a small current specified by a resistor R6 to obtain a load current corresponding thereto. Thus, even if a load is varied, a power source supply can be maintainly efficiently.
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