6 _ Transistor Small Signal Amplifier

Transistor Small Signal Amplifier Tutorial

The two transistor types have opposite polarity power supplies.
The polarity of the capacitors is reversed.
If the transistors have the same characteristics, then resistor values are the same in both circuits.

R1 and R2 are the base bias resistors, setting the bias point.
R3 is the collector load resistor.
R4 is the emitter stabilising resistor.
C3 is the emitter decoupling capacitor.
C1 and C2 are coupling capacitors which allow ac signals to pass but block dc.