Introduction to Op Amp IC 741
Op-Amp IC 741 or LM741 is one of the most used operational amplifier integrated circuits that perform both mathematical operations and amplification functions. This small chip mainly performs mathematical operations like addition, subtraction, multiplication, division, differentiation, integration, etc. in various circuits.
It is a high gain amplifier made up of BJT or FETS, which is often powered by both positive and negative supply voltage. It was first designed by Fairchild Semiconductor in the year 1963.
In this guide, we will learn about the Operational Amplifier IC or Op-Amp 741 or LM741 basics, characteristics, circuits, pins configuration & Applications. You can also check the LM358 Dual Audio Amplifier IC which has a pair of Op-Amp Circuit.
Characteristics
Input impedance is more than 100KΩ.
Output impedance is less than 100Ω.
The frequency range is between 0HZ to 1MZ.
Low offset voltage and current.
Voltage gain is about 2,00,000
Specifications
Power Supply: For proper functionality, it requires a minimum supply of 5V and can handle up to 18V.
Input Impedance: About 2 MΩ.
Output Impedance: About 75 Ω.
Voltage Gain: 2,00,000 for a minimal range of frequency.
Slew Rate (Rate at which op-amp can detect voltage change) : 0.5V/µs.
Input offset: In a range of 2mV-6mV.
Output Load: Recommended greater than 2KΩ.
Maximum Output Current: 20 mA.
Note: For the operational amplifier to function as a voltage amplifier, high input impedance and low output impedance values are recommended. This impedance makes op-amp IC 741 a near-ideal voltage amplifier.
Op Amp IC 741 Pin Configuration.
The symbol and pin configuration of op-amp 741 is shown below. The diagram comprises eight pins. Among these, pins 2,3, and 6 are the most significant pins, where pins 2 and 3 represent inverting and non-inverting terminals respectively, and pin 6 represents output voltage. Pin 8 is inactive in the circuit.
The number 741 in the name indicates that there are 7 active pins, 4 pins (pin 2,3,4,7) are capable of taking input and 1 pin ( pin 6) is an output pin. The triangular form in the IC represents an op-amp integrated circuit.
Power Supply Pins (Pin 4 and Pin 7):
Pin 4 and Pin 7 are negative and positive voltage supply terminals respectively. The power required for IC to operate is received from both these pins. The voltage level between these pins can be in the range of 5V to 18V.
Input Pins (Pin 2 and Pin 3)
Pin 2 and pin 3 are input pins for the op-amp IC. Pin 2 is considered as inverting input and pin 3 is considered as non-inverting input. When the voltage at pin 2 is greater than the voltage at pin 3, i.e. the voltage at inverting input is higher, then the output signal is low. Similarly, when the voltage at pin 3 is greater than the voltage at pin 2, i.e. the voltage at the non-inverting input is higher, then the output signal is high.
Output Pin (Pin 6):
Pin 6 is the output pin of op-amp IC 741.
The output voltage at this pin depends on the voltage level on input pins and the feedback approach used. When the voltage at this pin is high, this means that the output voltage is similar to the positive supply voltage. Similarly, when the voltage at this pin is low, this means that the output voltage is similar to the negative output voltage.
Offset Null Pin (Pin 1 and Pin 5)
Pin 1 and pin 5 are used for offset voltage in op-amp IC 741. Because of the higher voltage gain of op-amp IC 741, even minimal variation of voltage at inverting and non-inverting inputs caused due to abnormalities in construction procedure or other external disturbances can influence the output voltage. To overcome this effect, an offset value of voltage can be applied at pin 1 and pin 5, and this is generally done by using a potentiometer.
Not Connected Pin (Pin 8):
Pin 8 is not connected to any circuit inside op-amp IC 741. It is just a pin used to fill the void space in 8-pin standard packages.
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