43.4.2. Cutoff Frequency Modifications

Try these first

1. 1.

   What is the expected overall gain when cascading two CE amplifiers with gains of 5 each?

   Hint

   Consider what happens when the outputs interact.

2. 2.

   Define 'cutoff frequency' in the context of amplifiers.

   Hint

   Think of it as the boundary between passband and stopband frequencies.

3. 3.

   What is the effect of loading in a cascaded amplifier system?

   • It increases overall gain.
   • It has no effect on gain.
   • It decreases overall gain.

   Hint

   Consider how resistances from different stages interact.

4. 4.

   True or False: Buffers can increase the loading effect in cascaded amplifiers.

   • True
   • False

   Hint

   Think about the purpose of a buffer in signal isolation.

5. 5.

   Given two CE amplifiers with a gain of 15 each and an output resistance of 3kΩ and an input resistance of 1kΩ, calculate the actual overall gain.

   Hint

   This requires integrating the understanding of loading into calculations.

6. 6.

   Critically evaluate the combined cutoff frequency when the lower stage has a cutoff of 2kHz and the upper stage has a cutoff of 1kHz. Discuss the bandwidth impact.

   Hint

   Use the concept of the minimum cutoff frequency for cascaded systems in your evaluation.