Since the emitter connects to ground here, you can’t put, say, 0.3 V on the base and expect the emitter to somehow make up the other 0.4 V.

This architecture is useful for building stable and device-tolerant BJT Class A amplifiers. The circuit in Figure 1 sinks a constant current (ICE3) through Q3’s collector and emitter.

Figure 1 The addition of a simple diode in the emitter circuit yields the symmetric waveform in Figure 4. Figure 2 This amplifier circuit produces the distorted waveform in Figure 3. Diode D 1 ...

common emitter circuit 1 Articles An Excel Based High Frequency Transistor Amplifier Calculator July 31, 2014 by Mathieu Stephan 6 Comments ...