VHDL 91

Experiment No: 07

Title: Design, build and test Op Amp based Wein Bridge oscillator for given frequency.

AIM : Design, build and test Op Amp based Wein Bridge oscillator for given frequency.

APPARATUS REQUIRED:

Op-amp IC 741, Dual trace supply, Function Generator, Resistors, Capacitors, CRO, Probes

THEORY:

Equations Related to the Experiments:

a) Wein Bridge Oscillator

Closed loop gain A_v = (1+R_f/R₁) = 3

Frequency of Oscillation f_a = 1/(2pRC)

DESIGN:

Gain required for sustained oscillation is A_v = 1/b = 3

(PASS BAND GAIN) (i.e.) 1+R_f/R₁ = 3

\ R_f = 2R₁

Frequency of Oscillation f_o = 1/2p R C

Given f_o = 1 KHz

Let C = 0.05 mF

\ R = 1/2 p f_oC

R = 3.2 KW

Let R1 = 10 KW \ Rf = 2 * 10 KW

Circuit Diagram:

Model Graph:

PROCEDURE:

1. Connect the components as shown in the circuit Diagram
2. Switch on the power supply and CRO.
3. Note down the output voltage at CRO.
4. Plot the output waveform on the graph.
5. Redesign the circuit to generate the sine wave of frequency 2KHz.
6. Compare the output with the theoretical value of oscillation.

OBSERVATION:

Peak to peak amplitude of the output = Volts.

Frequency of oscillation = Hz.

Conclusion:

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