| 摘要 |
PURPOSE:To set two different gains by connecting a current mirror circuit to the 1st output stage of a differential amplifier to form the 2nd output stage and connecting an optional gain setting load resistor to the output stage. CONSTITUTION:A common connecting point of emitters of NPN transistors (TR) Q1, Q2 is connected to a constant current source 7 to constitute a differential amplifier circuit. The differential output between the TRs Q1, Q2 is subjected to current transmission by each current mirror circuit, collectors of a PNP TR Q4 and a TR Q9 are connected in common and connected to a gain resistor R3 to form one output terminal 5, which is connected to a base of the TR Q2 of the differential amplifier via a resistor R1 to constitute a DC feedback circuit. Collectors of a PNP TR Q5 and an NPN TR Q10 are connected in common as the differential output and connected to a gain setting load resistor R4 to constitute the other output terminal.
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