3.1. Positive Feedback

Try these first

1. 1.

   What is positive feedback?

   Hint

   Think about how signals reinforce each other.

2. 2.

   What is one of Barkhausen's criteria?

   Hint

   Consider the required gain for maintaining oscillation.

3. 3.

   What must the loop gain be for an oscillator to sustain oscillation?

   • < 1
   • = 1
   • ≥ 1

   Hint

   Think about what happens if the gain is less than one.

4. 4.

   In positive feedback, the feedback signal must be in phase with the input signal.

   • True
   • False

   Hint

   Consider what happens to feedback when signals are out of alignment.

5. 5.

   Design an oscillator circuit and analyze how to achieve Barkhausen’s criteria. Detail the components used and how they work together.

   Hint

   Think about how resistors and capacitors can influence gain and phase.

6. 6.

   Predict the outcome of a feedback circuit where the gain dips below 1. What implications does this have for the circuit's performance?

   Hint

   Analyze how feedback interacts with the circuit's loss elements.