Amplifier Circuits

Chapter 9 - Practical Analog Semiconductor Circuits

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Note, Q3 and Q4 in Figure below are complementary, NPN and PNP respectively. This circuit works well for moderate power audio amplifiers. For an explanation of this circuit see “Directly coupled complementary-pair,” Ch 4 .
Direct coupled complementary symmetry 3 w audio amplifier. After Mullard. [MUL]