27.7. Lower Cutoff Frequency Consideration

Try these first

1. 1.

   What does the emitter resistor do in a common emitter amplifier?

   Hint

   Think about the role of resistors in circuits.

2. 2.

   Define transconductance in your own words.

   Hint

   Focus on the relationship between input and output.

3. 3.

   What is the effect of adding an emitter resistor in a common emitter amplifier?

   • Increases gain
   • Decreases gain and stabilizes
   • Has no effect on gain

   Hint

   Think about the dual purpose of R_E.

4. 4.

   True or False: The lower cutoff frequency is determined by the coupling capacitors and resistors.

   • True
   • False

   Hint

   Recall how frequency affects the gain.

5. 5.

   If the emitter resistor is increased to stabilize the circuit against beta variations, how will the voltage gain change? Provide numerical reasoning for your answer.

   Hint

   Use example values for g_m and R_C to see the impact of varying R_E.

6. 6.

   Design an amplifier with a specific gain of 10 and a lower cutoff frequency at 100Hz. What components might you select and what considerations must be made?

   Hint

   Calculate based on the relationships discussed regarding gain and cutoff frequency.