COMMON EMITTER AMPLIFIER THAT IS OPERATED FROM PLURALITY OF POWER SUPPLIES

摘要

PURPOSE: To provide a simple and inexpensive circuit operatable from plural supply voltages without consuming a substantial power amount for the ability of being operated from the plural supply voltages. CONSTITUTION: An emitter 608-1 is connected to a DC power supply terminal 605 and the emitter 608-2 is connected to a battery 603. In the case that the battery is connected and a DC power supply is interrupted, a terminal 606 is at a low voltage, a transistor 613 is turned off and the transistor 612 performs a normal operation. A current is drawn from the higher one of two voltages applied to the emitters 608-1 and 608-2.