East West University
Department of Computer Science and Engineering
Semester : SPRING 15
Course Code : CSE251(1)
Course Title : Electronic Circuits
Experiment No. : 04
Experiment Name : Inverting and non-inverting Amplifier Circuit
using 741 Op Amp.
Student Name : Md. Rokon Uzzaman
Student ID : 2012-2-60-052
Group Number : 02
Group IDs : 2012-2-60-052
2012-2-60-001
2012-2-60-040
2012-1-60-016
Date of Performance : 02.03.2015
Date of Report Submission : 07.02.2015
Objectives
To familiarize with the 741 Op Amp Integrated Circuit (IC).
To design and construct an inverting amplifier using 741 Op Amp.
To Design and construct a non-inverting amplifier using 741 Op Amp.
Introduction
Operational Amplifier (Op-Amp) can perform mathematical operations such as addition,
subtraction, etc and which is also a differential amplifier. This is an integrated circuit (IC).
The block diagram of the 741 Op-Amp has 8 pins. We have to Place the Op-Amp on the trainer
board in such a way that the notch is in your left side in this way we can identify the pins of the
741 Op-Amp in the laboratory.
The names of different pins are as follows:
1. Offset null (usually not used)
2. Inverting input terminal
3. Non-inverting input terminal
4. Negative DC power supply (usually 5-15V negative)
5. Offset null (usually not used)
6. Output terminal
7. Positive DC power supply (usually 5-15V positive)
8. Not connected (NC)
Circuit Diagram:
Fig 2 : An inverting amplifier circuit
Fig 3 : A non-inverting amplifier circuit
Equipments
1. Digital trainer board.
2. DC power supply.
3. Signal generator.
4. Oscilloscope.
5. Digital multimeter.
6. 741 Op Amp (1 pc).
7. Resistor (as required from pre lab design).
8. Breadboard.
9. Connecting wires.
Lab Procedure:
1. At first we have to onnect the circuit as shown in Fig. 2 and Fig. 3 with the resistance.
Use a +15V DC power supply to terminal 7 and -15V DC power supply to terminal 4 of
the Op-Amp from the digital trainer board.
2. Then we have to use 5V peak to peak 1 kHZ sine wave from the signal generator and
observe the output in channel 2.
ANSWER TO THE POST LAB QUESTION:
Ans to the question no. 01
R1= 0.10 kΩ
Rf= 0.98 kΩ
Inverting
Vin= 80 mV
Rf
Vo= - *V
R 1 in
0.98
=- *80*10-3
0.10
= -0.784 V
Measured, Vo -0.8 V
Calculated, Vo -0.784 V
Measured and pre-lab Output Voltage is close to each other. So the design is verified.
Non-Inverting
Vin= 130 mV
Rf
Vo=(1+ )V
R 1 in
0.98
=(1+ ) 130*10-3
0.10
= 1.404 V
Measured, Vo 1.4 V
Calculated, Vo 1.404 V
Measured and pre-lab Output Voltage is close to each other. So the design is verified.
Ans to the question no.02
Inverting
Vin= 80 mV = 0.08 V
Measured, Vo = -0.8 V
Vo −0.8
Voltage Gain, AV = = = -10 V
Vin 0.08
Calculated, Vo = -0.784 V
Vo −0.784
Voltage Gain, AV = = = -9.8 V
Vin 0.08
Measured Voltage Gain, AV -10 V
Calculated Voltage Gain, AV -9.8 V
Measured and Calculated Voltage gain is close to each other. So the design is verified.
Non-Inverting
Vin= 130 mV = 0.13 V
Measured, Vo= 1.4 V
Vo 1.4
Voltage Gain, AV = = = 10.76 V
Vin 0.13
Calculated, Vo = 1.404 V
Vo 1.404
Voltage Gain, AV = = = 10.8 V
Vin 0.13
Measured Voltage Gain, AV 10.76 V
Calculated Voltage Gain, AV 10.8 V
Measured and Calculated Voltage gain is close to each other. So the design is verified.
Ans to the question no.03
Ans to the question no.04
In an ideal op-amp gain is infinity. We know gain, AV=Vo/Vin.Which means Vo/Vi=infinity So Vi=0.
We know that Vi = V1-V2
V1-V2 = 0 in an op-amp.So V1=V2 (V1 is Actually Grounded)
V1=0 (Actual Ground)
and V2=0 (Virtual Ground).
When one terminal is grounded the other terminal is assumed to be at ground potential and
that is virtual ground concept of op-amp.
Discussion:After doing this experiment, I have learned to design and construct an inverting
and non-inverting amplifier using 741 Op Amp.
