(a) Explain the meaning of the terms negative and positive feedback as they apply to amplifier circuits. Briefly describe one application of positive feedback that you have encountered.
(b) Outline three advantages of employing negative feedback in an operational amplifier circuit. Why is it often necessary to reduce the gain of an operational amplifier from its open-loop value?
(c) Derive an expression for the voltage gain of an amplifier employing voltage series negative feedback and thus show that the closed-loop gain is independent of the open- loop gain, provided that certain conditions are obeyed: list the necessary conditions
(d) If the open-loop gain of an amplifier of this type is 4 x 10^5, and the fraction of the output voltage fed back to the input is 0.01, calculate the change in gain of the feedback amplifier if the open-loop gain changes by 30%.