13-09-2013, 02:48 PM
WEIN BRIDGE OSCILLATOR
AIM: To study and calculate frequency of. Wein Bridge Oscillator.
THEORY:
57The wein bridge oscillator is a standard circuit for generating low
frequencies in the range of 10 Hz to about 1MHz.The method used for getting
+ve feedback in wein bridge oscillator is to use two stages of an RC-coupled
amplifier. Since one stage of the RC-coupled amplifier introduces a phase shift
of 180 deg, two stages will introduces a phase shift of 360 deg. At the
frequency of oscillations f the +ve feedback network shown in fig makes the
input & output in the phase. The frequency of oscillations is given as
f =1/2π√R1C1R2C2
In addition to the positive feedback
PROCEDURE:
1. Connections are made as per the circuit diagram
2. Feed the output of the oscillator to a C.R.O by making adjustments in the
Potentiometer connected in the +ve feedback loop, try to obtain a stable
sine Wave.
3. Measure the time period of the waveform obtained on CRO. & calculate the
Frequency of oscillations.
4. Repeat the procedure for different values of capacitance.
RESULT:
The frequency of the wein bridge oscillator is calculated and is verified