NAME: ____________________________________

1) (1 pt) What is the basic equation that relates the collector current to the base-emitter voltage in a BJT?

2) (6 pts) For EACH of the following small signal parameters of a BJT: transconductance, emitter resistance, input resistance, and output resistance:

1. What is the definition of this parameter?
2. Derive the relationship between this parameter and the transistor's DC operating point parameters

g_m:

 

r_e:

 

r_pi:

 

r_o:

 

3) (1 pt) What is ( r_o * g_m )? (Expressed in terms of DC operating point parameters)

4) (1 pt) SHOW that the transconductance in parallel with the input resistance is identical to the emitter resistance.

5) (1 pt) Since the differential voltage gain of an actively loaded BJT differential pair is given by A_d = g_mR_o it is recommended by a colleague that you can get a very large gain simply by using a very large valued resistor from the output to ground. What is the flaw in this reasoning?