27.2.3. Input Resistance and Output Resistance

Try these first

1. 1.

   What is the formula for calculating input resistance in a CE amplifier?

   Hint

   Think about how the emitter resistor affects input resistance.

2. 2.

   Why is having a high input resistance important?

   Hint

   Consider the signal's journey into an amplifier.

3. 3.

   What role does the emitter resistor (R_E) play in a CE amplifier?

   • Increases bandwidth
   • Stabilizes operating point
   • Decreases input resistance

   Hint

   Think about the implications of resistance in biasing circuits.

4. 4.

   True or False: The output resistance is determined solely by the collector resistor (R_C).

   • True
   • False

   Hint

   Consider the components that interact at the output.

5. 5.

   Design a CE amplifier with R_E = 200Ω providing a gain of at least 50. Considering R_C needs to be much higher than R_E, suggest values while maintaining stability.

   Hint

   Remember that increasing R_C directly boosts gain while ensuring R_E supports stability against variations.

6. 6.

   Analyze how introducing a capacitor across R_E would change the amplifier's input and output characteristics.

   Hint

   Consider the frequency-dependent behavior of capacitors in AC circuits.