ADDIS ABABA UNIVERSITYINSTITUTION OF TECHNOLOGY

DEPARTMENT OF ELECTRICAL & COMPUTER ENGINEERING

LABORATORY REPORT

Course number: Eceg: - 2206

Experiment Number: 04

Title: Operational Amplifier

By: _

Group No. :

Date of Experiment. 08/22-04-2012

Date of Submission. 28-04-2012

USED EQUIPMENT & COMPONENTS

No Description1 Operational amplifier board2 2 Variable DC Power source3 Electronic or Voltmeter4 Cathode Ray Oscilloscope5 Function Generator6 Conducting Wires7 Decade Resistor8 Transistor, 2.2k, 120, 82K, 100K,33K, 1k & 1.0K9 Circuit Board

DIFFERENCIAL AMPLIFIER

An operational amplifier, or op-amp, is a very high gain differential amplifier with high input impedance and low output impedance. Typical uses of the operational amplifier are to provide voltage amplitude changes (amplitude and polarity), oscillators, filter circuits, and many types of instrumentation circuits. An op-amp contains a number of differential amplifier stages to achieve a very high voltage gain. A basic op-amp with two inputs and one output as would result using a differential amplifier input stage. The operational amplifier is an extremely efficient and versatile device. Its applications span the broad electronic industry filling requirements for signal conditioning, special transfer functions, analog instrumentation, analog computation, and special systems design. The analog assets of simplicity and precision characterize circuits utilizing operational amplifiers.

Figure 1, Basic op-amp., Op Amp Package

Single-ended input operation results when the input signal is connected to one input with the other input connected to ground.

Figure 2, Single-ended operation.

CALCULATIONSGain(A) = Vo / Vi

= -Rf /R2

Vo= Vi 1 + Vi 2

Vo = (-R1/R2)Vi 1 + (-R1/R3)Vi 2

Vo=f(Vin)

PROCEDUREInverting amplifier

1. setup the circuit according to circuit figure 3, and VCC set to 12V and plot the transfer characteristic voltage

Vo = f (Vin) -12 <= Vin <= 12V

a) R2 = 50KΩ R1 = 100kΩ

b) R2 = 50KΩ R1 = 50kΩ

c) R2 = 100KΩ R1 = 50kΩ

2. The signal generator connects at the input terminal generating a 100Hz, 16Vpp. And Connect to the oscilloscope and sketch.

Figure 3. Inverting Amplifier

12v

Vo

-12v

R2

R1

Vi

-+

Summation3. setup the circuit according to circuit figure 4

a) Vi1 = -1.5v, Vi2 = -2.8v A=1

b) Vi1 = -4.5v, Vi2 = +3.5v A=2

4. Measure the output voltage Vo

Figure 4. Inverting Summing Amplifier

Non-Inverting Amplifier5. Setup the circuit according to circuit figure 5 and plot the transfer characteristic voltage

Vo = f (Vin) -12 <= Vin <= 12V take R1 = R2 = 50kΩ

6. Apply a sinusoidal input signal input signsl of 100Hz and 16Vpp and observe the output voltage.

Figure 5. Non-Inverting Amplifier

12v

Vo

-12v

R2

R3

R1

Vi 2

Vi 1

-+

12v

Vo

-12v

R2

R1

Vi

+-

R2

R1

Integrator7. Setup the circuit according to circuit figure 6 with R1 = 100k, R2 = 500Ω C=10nF

8. Apply a sinusoidal input signal input signsl of 50kHz and 10Vpp and observe the output voltage Vo & Vin.

9. Apply a square wave from 5kHz and 1Vpp and observe the output voltage Vo and Vin.

10. Vary the square wave from 500Hz to 50kHz and 10Vpp and observe the output voltage Vo

Figure 5. OP-Amp Integrator

RESULTS1, A,

Vin -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12

Vo 11.8 11.8 11.8 11.8 8.3 4.3 0 4.1 8.4 10.2 10.2 10.2 10.2

B,

Vin -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12

Vo 11.6 11.6 8 6 4 2 0 2 4 6 8 10 12

C,

Vin -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12

12v

Vo

-12v

R1

C1

Vi

-+

Vo 5.9 5.1 4 3 2 1 0 -1 -2 -3 -4 -5 -6

2, output signal

3, a, Vo= 4.3Volt

B, Vo= 8 Volt

4, a, Vo= 4.44Volt

B, Vo= 8.66Volt

5,Vo=f(Vin)

Vin -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12

Vo -10.13 -10.13 -10.13 -10.13 -8.6 -4.5 0 4.52 8.6 10.5 10.5 10.5 10.5

6 , output signal

8, input signal 2*5=10volt output signal 4.6 * 5 =23

9, input signal output signal

10, output volt square wave signal from 500Hz to 50 KHz

CONCLUSIONAn operational amplifier, or op-amp, is a very high gain differential amplifier with high input impedance and low output impedance. Typical uses of the operational amplifier are to provide voltage amplitude changes (amplitude and polarity), oscillators, filter circuits, and many types of instrumentation circuits. An op-amp contains a number of differential amplifier stages to achieve a very high voltage gain. The operational amplifier is an extremely efficient and versatile device. Its applications span the broad electronic industry filling requirements for signal conditioning, special transfer functions, analog instrumentation, analog computation, and special systems design. The analog assets of simplicity and precision characterize circuits utilizing operational amplifiers.