27.8. Summary of Changes

Try these first

1. 1.

   What does the negative sign in voltage gain signify?

   Hint

   Think about the signal direction.

2. 2.

   What is the purpose of the emitter resistor R_E?

   Hint

   Consider stability and variations in β.

3. 3.

   What is the primary task of the emitter resistor R_E in a Common Emitter Amplifier?

   • Increase gain
   • Stabilize operating point
   • Reduce output
   • Increase input resistance

   Hint

   Think about what happens to the circuit without R_E.

4. 4.

   True or False: The output voltage of a Common Emitter Amplifier is in phase with the input.

   • True
   • False

   Hint

   Consider the behavior of an inverting amplifier.

5. 5.

   Given a Common Emitter Amplifier with R_C = 10kΩ, g_m = 0.02 S, and R_E = 1kΩ, calculate the voltage gain. Discuss if the gain would be acceptable if R_E were increased.

   Hint

   Use the gain formula and substitute values for full calculations.

6. 6.

   Analyze the input resistance for a Common Emitter Amplifier with R_BB = 100kΩ, β = 50, r = 150Ω, and R_E = 200Ω. What would happen if R_E were removed?

   Hint

   Focus on parallel resistance calculation including the base resistance.