WEIN BRIDGE OSCILLATOR
AIM: To study and calculate frequency of.
Oscillator. Wein Bridge
Transistor (BC 107) 2 No
Resistors 10K 4 No
1 K 3 No
2.2 K 2 No
Capacitors 10 2 No
0.01 2 No
RPS (0 – 30 V)
The 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
In addition to the positive feedback
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.
Given R=10kΩ, C=0.01μF
fT = 1/ 2pRC
fP = =
MODEL WAVE FORM:
The frequency of the wein bridge oscillator is calculated and is verified