28.2.10. Conclusion on Stability

Try these first

1. 1.

   What is the primary disadvantage of fixed bias in transistors?

   Hint

   Consider how changes in transistor characteristics can affect current.

2. 2.

   Describe what is meant by the term saturation in a common emitter amplifier.

   Hint

   Think about how the output voltage behaves under high current conditions.

3. 3.

   What happens to the operating point in a fixed bias circuit when beta increases?

   • It remains stable
   • It may saturate
   • It decreases

   Hint

   Think about the consequences of increased current demand.

4. 4.

   True or False: Cell bias is more reliable than fixed bias under varying temperature conditions.

   • True
   • False

   Hint

   Consider which bias method adjusts dynamically to changes.

5. 5.

   If you have a common emitter fixed bias amplifier with a supply voltage of 12V and a beta of 150, calculate the maximum collector current if the transistor saturates. Explain your reasoning.

   Hint

   Consider the drop across your load when current saturates.

6. 6.

   Design a cell-biased amplifier aimed to maintain 4mA collector current despite changes in beta between 100 and 300. Discuss the selection of resistances needed.

   Hint

   Use the feedback principle to ensure stable operation across beta changes.