28.2.6. Cell Bias Circuit Analysis

Try these first

1. 1.

   What is the main disadvantage of fixed bias in amplifiers?

   Hint

   Consider the impact of changing transistor parameters.

2. 2.

   Define cell bias.

   Hint

   Think about how resistors are used in the circuit.

3. 3.

   What is the primary advantage of cell bias over fixed bias?

   • It uses less power
   • It provides better stability
   • It is easier to design

   Hint

   Think about how each biasing method responds to changes in transistor parameters.

4. 4.

   True or False: Fixed bias circuits are highly stable under temperature variations.

   • True
   • False

   Hint

   Consider the changes in transistor characteristics over time.

5. 5.

   If a common emitter amplifier with fixed bias has a supply voltage of 12V and a collector resistor of 3.3k Ohms, calculate the maximum expected collector current before saturation when beta is 150.

   Hint

   Consider the voltage drop across the resistors in conjunction with the supply voltage.

6. 6.

   Design a cell bias circuit using standard resistor values that maintains an exact collector current of 2 mA when beta varies from 100 to 200.

   Hint

   Use simultaneous equations involving beta and the defined target currents.