Laboratory Manual - King Fahd University of Petroleum and Minerals

KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS
DEPARTMENT OF ELECTRICAL ENGINEERING
Electronic Circuits II – EE303
Experiment # 3
Linear Applications of Operational Amplifier
OBJECTIVE
1. To measure the characteristics of several linear circuits based on the operational
amplifier namely inverting amplifier, inverting summer, inverting integrator,
inverting differentiator and differential amplifier.
2. Learn factors involved in circuit design using op amps.
3. To design circuits to implement simple linear functions.
BACKGROUND
This section provides brief discussion of the main characteristics of the op amp based
circuits shown in Figure 1:
Unity-gain Buffer:
It has a voltage gain, input resistance and output resistance of A v / v 1, R and
R
o
0 , respectively. It does not take any input current and can drive any desired load
resistance without loss of signal voltage. Thus, it used to provide excellent impedancelevel
transformation while maintaining signal voltage level.
Inverting Amplifier:
It has a voltage gain, input resistance and output resistance of A v / v R / R
v
o i
2 1,
R i
R 1
and R
o
0 , respectively. The minus sign means a 180 o phase shift between the
output and input signals
Summing Amplifier:
The output voltage can be expresses as v o
[( R3 / R1
) v1
( R3
/ R2
) v2]
.
It can be seen that the scale factors for the two inputs can be independently adjusted by
proper choice of R 2 and R 1 . Also, more inputs can be added simply by connecting them
same way as v 1 and v 2 . Hence, it can be used as a simple digital-to-analog converter.
Inverting Integrator:
v
o
i
i
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