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sine wave oscillator support required

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raviK

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i want to design a wein bridge oscillator in proteus simulator.
but output is not oscillating.

kindly help me.
 

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For starters, the forward gain needs to be greater than 3. Yours is exactly 3.0000
I dont see how your opamp is getting DC power.
Power the opamp on split supplies, and dispense with the 0.833V bias.
 
i tried to increase gain, but still there is no oscillation. O/P voltage increased from 2.5V to 2.9 volt. But no oscillation in oscilloscope
 
power supplied +5V & Ground because i need single power supply circuit, without negative rail voltage.
 
Your simulator needs to be kicked to get the oscillation started. In an actual circuit then noise will get it started but the simulation does not have any noise.
With a gain of 3.1 times and the 0.833V bias then the output will have clipping distortion.
Maybe your sim software does not know that the inputs of the TLC2201 opamp work all the way down to its negative supply that is ground in your circuit.
 
Read this.

This is what it takes to make it work.
1. Proper bias. This can be properly implemented in a real circuit without using split supplies.
2. Gain slightly higher than 3
3. Initial conditions to create a slight pertubation so that the oscillator starts. The real circuit has enough noise to self-start, but a mathematical model (Spice simulation) does not.
332.gif
4. Note that without automatic gain control, the output waveform is clipped, so a practical oscillator also needs to have that added.
332a.gif
 
As AL pointed out
Phase shift oscillators only work in theory unless there is proper bias and excess gain with gain limiter to obtain gain of 1.0000... at point of stable amplitude out.
300px-Wien_Bridge_Oscillator_with_diode_limiting.png

Naturally this introduces a measureable harmonic distortion determined by amount of compression and response time of compression.

Low Q design is not great here for best linearity but it works.... for a low quality sinewave.
 
kindly help me.
In real life op amp that have very high gain will imminently go into no oscillations or square wave output, that is because any instability can cause it to happen and real life is full of instabilities :)
Simulators can give you oscillation, but what simulators know about real life?!
 
Simulations can be as perfect as your model.
The step voltage to create DC bias in a closed loop or bias point has all the energy needed to initialize an oscillation if the Barkhausen criteria is satisfied.
But for stable amplitude and phase, low THD, linear operation, better methods exist.
 
Doesn't say much for simulators when somebody like you has to defend them.
Au Contraire, I know their value. I never build any electronic project without simulating it first....
 
Au Contraire, I know their value. I never build any electronic project without simulating it first...
I'm with you there Mike but, I also realize that SIMs (all of them, best I can tell) will, occasionally, allow circuits that do not hold up to real world builds.
 
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