An operational amplifier is a direct coupled high gain negative feed back amplifier.It can amplify the signals having the frequency range from 0 HZ to 1MHZ. It is a basic linear integrated circuit.An operational amplifier is so named because it was originally designed to perform mathematical operation like addition,subtraction,differentiation,integration,multiplication,division in analog computers.
shows the block diagram of an operational amplifier.
The schematic diagram of op-amp is shown in the fig.
It contains two inputs,namely inverting input and non inverting input and only one output.The signal given to the inverting input is always inverted at its output.A positive voltage at its input produces negative output voltage and similarly a negative input produces a positive output.The signal given to the non-inverting input is available at the output any changes in its sign.All the function of the op-amp depend upon the external connected components.
The following points may be noted about op-amp :- The input stage of an Op-amp is a differential amplifier and the output stage is typically a class B push pull emitter follower.
- The internal stage of an Op-amp are direct coupled which means no coupling capacitors are used.
- An Op-amp has very high input impedance and very low output impedance.
- An Op-amp has very high open loop voltage gain ,typically more than 200,000.
- An Op-amp are almost operated with negative feed back.It is because open loop voltage gain of these amplifiers is very high.
IC 741 -Operational amplifier - pin details :
IC 741 operational amplifier is a 8 pin dual in line packages IC.The pin diagram of IC 741 is shown in fig
The pin details are given below
pin no 1 : Off set null balance
pin no 2 : Inverting input
pin no 3 : Non inverting input
pin no 4 : Negative supply
pin no 5 : Off set null balance
pin no 6 : output
pin no 7 : positive supply
pin no 8 : No connection
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