| 摘要 |
PURPOSE:To eliminate a power voltage supply terminal as the external lead terminal of an amplifying circuit, by supplying electric power from an output stage collector to a front amplification stage through a constant-voltage power source circuit. CONSTITUTION:A constant-voltage power source circuit 21 is one outputting a prescribed a DC output voltage even if its input voltage varies; its input is connected to the collector of an output transistor (TR)12 and its DC output is supplied to the 1st TR6 and 2nd TR7 through a common emitter resistance 10 and a voltage dividing resistance 8, operating an initial differential amplification stage. At this time, the collector potential of an output TR12 is stabilized by the constant-voltage power source circuit 21 to be held at the constant potential of a point P, so that the initial differential amplification stage operates stably. For this purpose, a collector load resistance 13 is provided externally to remove a power voltage VCC supply terminal 18 from external lead terminals. |
