63.3. Introduction

Try these first

1. 1.

   What is the primary function of a cascode amplifier?

   Hint

   Think about what happens when you stack amplifiers.

2. 2.

   Define small-signal parameters in the context of amplifiers.

   Hint

   These parameters help simplify complex circuits.

3. 3.

   What is the primary advantage of using a cascode amplifier compared to a common emitter amplifier?

   • Lower output resistance
   • Higher input capacitance
   • Better high-frequency performance

   Hint

   Think about how cascading amplifiers affects their operating characteristics.

4. 4.

   True or False: The early voltage is directly related to output resistance in a BJT.

   • True
   • False

   Hint

   Consider the role of early voltage in the transistor characteristics.

5. 5.

   If the early voltage is increased, what is the expected impact on the output resistance and operating speed of the cascode amplifier?

   Hint

   Consider how resistance and speed correlate in amplifier design.

6. 6.

   Calculate the total input capacitance of a BJT cascode amplifier with C_pi = 10 pF and C_mu = 5 pF, considering the voltage gain of the amplifier is 100.

   Hint

   Apply the formula for input capacitance with gain.