27.6.1. Output Resistance in Presence of Emitter Resistor

Try these first

1. 1.

   What does an emitter resistor do in a transistor circuit?

   Hint

   Think about its role in thermal stability.

2. 2.

   Define transconductance.

   Hint

   It’s a key factor in understanding amplifier gain.

3. 3.

   What is the effect of the emitter resistor on the voltage gain in a common emitter amplifier?

   • Decreases gain
   • Increases gain
   • No effect
   • Only affects DC output

   Hint

   Think about how R_E modifies the gain equation.

4. 4.

   True or False: A coupling capacitor allows DC signals to pass while blocking AC signals.

   • True
   • False

   Hint

   Remember the function of a coupling capacitor in AC vs DC.

5. 5.

   Given a common emitter amplifier with R_E = 2kΩ and R_C = 10kΩ, calculate the voltage gain assuming g_m = 0.035 S.

   Hint

   Plug values into the voltage gain formula.

6. 6.

   If the emitter resistor must be reduced to recover gain, what might happen if it is made very small? Discuss possible circuit behavior.

   Hint

   Consider thermal stability and sensitivity factors in transistor circuits.