Electronic Circuits II
1. Define positive feedback?
If the feedback signal is in phase with input signal, then the net effect of the
feedback will increase the input signal given to the amplifier. This type of feedback is
said to be positive or regenerative feedback.
2. Define negative feedback?
If the feedback signal is out of phase with the input signal then the input
voltage applied to the basic amplifier is decreased and correspondingly the output is
decreased. This type of feedback is known as negative or degenerative feedback.
3. Define sensitivity?
Sensitivity is defined as the ratio of percentage change in voltage gain with
feedback to the percentage change in voltage gain without feedback.
4. What are the types of feedback?
i.
Voltage-series feedback
ii.
Voltage-shunt feedback
iii.
Current-series feedback
iv.
Current-shunt feedback
5. Define feedback?
A portion of the output signal is taken from the output of the amplifier and is
combined with the normal input signal. This is known as feedback.
6. Write the expression for input and output resistance of voltage series feedback
amplifier.
Input resistance with feedback, Rif $ 5i
Output resistance with feedback, Rof = Ro $
7. Give an example for voltage-series feedback.
The Common collector or Emitter follower amplifier is an example for
voltage series feedback.
8. Write the expression for input and output resistance of current shunt feedback
amplifier.
Input resistance with feedback, Rif = Ri $
Electronic Circuits II
Output resistance with feedback, Rof = Ro $
9. Give the properties of negative feedback.
i.
Negative feedback reduces the gain
ii.
Distortion is very much reduced
10. Give the effect of negat