Operational Amplifier (OP-AMP)
An Operational Amplifier is basically a three-terminal device that consists of two high impedance inputs. One of the inputs is called the Inverting Input, marked with a negative or “minus” sign, (–). The other input is called the Non-inverting Input, marked with a positive or “plus” sign (+).
The operational amplifier is a high voltage gain, direct-coupled amplifier which can be used to perform mathematical operations on analog signals. It can be used to amplify both DC and AC signals.
OP-AMP Pin Configuration
• The most commonly used op-amp is IC741. It is an 8 pin IC.
In a typical Op Amp, there will be 8 pins. These are
Pin1 – Offset Null
Pin2 – Inverting input
Pin3 – Non inverting input
Pin4 – Ground- Negative supply
Pin5 – Offset Null
Pin6 – Output
Pin7 – Positive supply
Pin8 – Strobe
PROPERTIES OF OP-AMP
• Infinite open-loop gain G = vout/vin
• Infinite input impedance Rin, and so zero input current.
• Zero input offset voltage.
• Infinite output voltage range.
• Infinite bandwidth with zero phase shift and infinite slew rate.
• Zero output impedance R. out
• Zero noise.
• Infinite common-mode rejection ratio (CMRR).