| 摘要 |
PURPOSE:To attain excellent amplification without flowing a waste current to a bias current circuit and giving variation to a bias current by applying a bias current of a power amplifier transistor (Tr) with a Tr, a resistor and a constant current source. CONSTITUTION:A TrQ20 of diode connection is inserted between Trs Q8 and Q9, the emitter of a TrQ3 is connected to the base of a TrQ4 and a collector of a TrQ6 is connected to a base of a TrQ10. Thus, the bias current circuit comprising power amplifier Trs Q4, Q10 is constituted by Trs Q1, Q3, Q5-Q9, Q20, a resistor R1 and constant current sources 11, 12. As a result, only a base current of the TrQ9 flows respectively to the Trs Q7, Q8, Q20 and only a base current of the TrQ10 flows to the Trs Q5, Q6, then the waste current to the bias current supply circuit is eliminated. The stable bias current is attained by setting each base potential of the Trs Q4, Q10 by the base-emitter voltage of the Trs Q1, Q3, Q5-Q9, Q20.
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