Transistor amplifier with amplifier stages - has output stage coupled to emitter circuit of input stage

摘要

The output circuit (15) of the output amplifier stage (4) employs an output transformer (5) and the output circuit is coupled to the emitter circuit (16) of the input amplifier stage (2) via a coupling network (17). This comprises a voltage coupling circuit (8) for the voltage of the output circuit (15) and current coupling circuit (20) for supplying a voltage proportional to the current in the output circuit (15) via a resistor (19) connected in series with the primary winding of the output transformer (5). A variable resistor (24) is used to adjust the amplification factor of the amplifier. In the current coupling circuit (20) a transformer (25) is inserted between the series resistor (19) and the emitter circuit (16) of the input stage (2).