» Open and closed loop configurations

Op-amp in closed loop configuration

arjun — Wed, 15 Oct 2008 17:12:58 +0000

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 read more

Open Loop Op-Amp Configurations

arjun — Tue, 14 Oct 2008 17:35:05 +0000

When connected in open-loop configuration,the op-amp functions as a high gain amplifier.These are three open loop op-amp configurations. Differential Amplifier Inverting Amplifier Non-Inverting Amplifier These configurations are classed according to the number of inputs used and the terminal to which the input is applied when a single input is used. Disadvantages of open loop configurations The open loop of the op-amp is very high.Therefore only the smaller signals having low frequency may be amplified accurately without distortion. Open loop Voltage gain of the op-amp is not a constant voltage gain varies with changes in temperature and power supply as well as mass production techniques.This makes op-amp unsuitable for many linear applications Bandwidth of most open loop op-amps read more