• There are four basic ways of connecting the feedback signal.Both voltage and current can be fedback to the input either in series or parallel.Specifically there can be 1. Voltage Series Feedback : In this type a part of output voltage fed back in series with the input signal,resulting in overall gain reduction.It reduces the output impedance and increase the input resistance.

1. Voltage Shunt feedback: In this type a part of output voltage fedback in shunt (parallel) with an input signal.The voltage-shunt feedback provides a stabilised overall gain and decrease both input and output resistance.

1. Current Series Feedback: In current series feedback a voltage is develop which is proportional to the output current. This is called current feedback even though it is a voltage that substracted from the input voltage.Because of the series connection at the input and output,the input and output resistance get increased.This type of amplifier is called transconductance amplifier.

Current Shunt negative feedback:It is called as series derived,shunt fed feedback.The shunt connection at the input reduces the input impedance and series connection at the output increases the output impedance.

The input and output impedance for each type is given by following table.

The feedback factor for each configuration is shown in the each figure