Op-amp is in closed loop configuration when there is a connection either direct or via another network exist between the input and output terminals.We can control the gain of op-amp if we introduce a modification in the basic circuit.This modification involves a feedback ie the input signal is fed back to the input either direct or via another network.
Different feedback configurations
An op-amp that uses feedback is called a feedback amplifier.A feedback amplifier is sometimes referred to as a closed loop amplifier because the feedback forms a closed loop between the input and the output.A close loop amplifier can be represented by using two blocks one for op-amp and the other for a feedback circuit.These connections are classified according to whether the voltage or current is fed back to the input in series or parallel.
- Voltage series feedback
- Voltage shunt feedback
- Current series feedback
- Current shunt feedback.
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April 16th, 2009 at 6:24 pm
Dear Friend,
In the above diagrams you were giving a.c. supply or sinusoidal voltage as input signal to the op amp and hence there is no need to indicate “+” and “-” at the signal.
Conceptually, things are good but it would be nice if some introduction to the applications of these configurations was also available.