Solved Examples on Wien Bridge Oscillator
A Wien Bridge Oscillator circuit is required to generate a sinusoidal waveform of 3,200 Hertz (3.2kHz). Calculate the frequency and determine the resistors R1 and R2 and the capacitors C1 and C2.
Given fr = 3.2 kHz
If resistors R1 = R2 and capacitors C1 = C2 and Assume a value for the feedback capacitors of 3.8nF, then the corresponding value of the feedback resistors is calculated,
We know,
[Tex]f_{r}=\frac{1}{2\pi RC}[/Tex]
Here C= 3.8nF, fr = 3.2 kHz,
[Tex]3.2\times 10^{3}=\frac{1}{2 \pi \times R \times 3.8\times 10^{-9}} [/Tex]
R = 13088 Ω (or) 13.1 kΩ
To get the sinusoidal wave the voltage gain of the Wien bridge Oscillator is greater than or equal to 3,
[Tex]A_{V} \geq 3[/Tex]
[Tex]\frac{V_{out}}{V_{in}}\geq 3[/Tex]
[Tex]1+\frac{R_{3}}{R_4}\geq 3[/Tex]
Take,
[Tex]1+\frac{R_3}{R_4}=3[/Tex]
[Tex]\frac{R_3}{R_4}=3-1[/Tex]
[Tex]\frac{R_3}{R_4}=2[/Tex]
[Tex]R_4=\frac{1}{2}R_3[/Tex]
If R3 = 80 kΩ, then R4 = 40 kΩ.
In the Wien Bridge oscillator, R1 = R2 = 200k Ohms and C1 = C2 = 600 pico Farads. Find the oscillating frequency of the circuit.
Given,
Resistance is,
[Tex] R= R_1 = R_2 = 200\text{k Ohms} = 200 \times 10^{3}[/Tex]
Capacitance,
[Tex]C=C_1 = C_2 = 600 \ \text{pico Farads}=600\times 10^{-12}=6\times 10^{2}\times 10^{-12}=6\times 10^{-10}[/Tex]
To find the frequency, use the formula,
[Tex]f=\frac{1}{2\pi RC}[/Tex]
Substitute R,C values in f,
[Tex]f=\frac{1}{2\pi \times 200\times 10^{3}\times 6 \times 10^{-10}}[/Tex]
f=1326 Hz
The frequency of oscillation is, 1326 Hz (or) 1.326 kHz
Wien Bridge Oscillator
In this article, we will go through the Wien Bridge Oscillator, first, we will start our article with the introduction of the bridge oscillator frequency, then we will go through the RC phase shift network and oscillator output gain and phase shift, then we will see Wien bridge oscillator frequency, then we will go through RC network and construction of bridge oscillator frequency using IC 741 operational amplifier, at last, we will conclude our article with solved examples, advantages, disadvantages and some FAQs.
Table of Content
- Wien Bridge Oscillator
- RC Phase shift Network
- Oscillator Output Gain and Phase Shift
- The RC Network
- Construction
- Solved Examples
- Advantages of Wien Bridge Oscillator
- Disadvantages of Wien Bridge Oscillator
- Applications of Wien Bridge Oscillator