19.1.4. Base to Emitter Resistance

Try these first

1. 1.

   What is the base to emitter resistance in a BJT?

   Hint

   Think about where the base current is going.

2. 2.

   Define transconductance.

   Hint

   How does this relate to current and voltage?

3. 3.

   What is the small signal model primarily used for?

   • To calculate DC current
   • To linearize the non-linear circuit
   • To design digital circuits

   Hint

   Think about why we need to simplify complex behaviors.

4. 4.

   True or False: Transconductance is independent of the Q-point.

   • True
   • False

   Hint

   Remember how parameters may change with operating conditions.

5. 5.

   If a BJT circuit has a quiescent current of 1mA and the base-emitter voltage is 0.7V, calculate the transconductance and the base-emitter resistance.

   Hint

   Recall how to derive these values from the definitions.

6. 6.

   Discuss how changing the Q-point affects the linearity of the output. Include graphs to illustrate your answer.

   Hint

   Visualize different Q-points on the I-V characteristics to see variations.