wein bridge

[threephase03]

Hi Everyone

I'm trying to build a 50hz Wein Bridge Oscillator, can anyone tell me if my schematic is wrong. Ive come across a few examples and I dont know which
one i should follow. 

Any help would be greatly appreciated.

Cheers.

[threephase03]

I've found a better example that I will follow

thanks to everyone that looked

[Terry Bites]

That looks right but the text book version needs a small addition to work reliably.

Practical Wien bridge oscillators need amplitude stabilisation.
Without it the waveform will distort or even collapse.
Here is one simple solution. Any general purpose jfet will do. Tweak R2 for amplitude.
You sometimes see a flash-light bulb used to achieve the same thing.
But we are in the modern world.

[TimFox]

Yes, it is “Wien” bridge, not “Wein”.

[threephase03]

Thanks for the responces

[nonius_]

Yes, it is “Wien” bridge, not “Wein”.

Griechischer Wein?   ....Schenk noch mal ein..... 

Any help would be greatly appreciated.

Do yourself a favour and use understandable schematics. Where opamps are drawn as triangles and without the spaghetti. The schematic you originally posted can't be understood without a lot of extra effort. Effort I'm not going to put into it.

can anyone tell me if my schematic is wrong

I'd have to redraw it first into something that I could understand.

You sometimes see a flash-light bulb used to achieve the same thing. But we are in the modern world.

Nothing wrong with using a small incandescent bulb for stabilization, it's a simple and effective solution. Some of the greatest minds in electronics test equipment have used the principle (Bill Hewlett and David Packard). In fact, the simple light-bulb was the basis of the HP200 oscillator, which formed the start of the HP company....

I've built the Elektor Spot-sinus generator in the past with good results.  Not sure how much or little distortion is acceptable for OP, though. That depends entirely on the use it's intendend for, of which we know nothing.

https://drive.google.com/file/d/1nfFLhheT4U1b-r4cJfcoX59vCXgcDNrq/view, see page 56.

[Zenith]

The gain of a Wien Bridge oscillator needs to be set to exactly 3, which can't be done with precision pots. If it's not spot on 3 the amplitude will increase until clipping occurs or will drop away to nothing.

There are several ways of doing this. An incandescent bulb, a special self-heating thermistor (now hard to find). A JFET used as a voltage controlled resistor. An LED and CdS arrangement with a filter. Back to back diodes.

All have advantages and disadvantages. Generally, lower distortion involves higher cost and complexity, and can involve the amplitude bouncing for a time until it settles when changing frequency.

https://www.analog.com/en/resources/analog-dialogue/studentzone/studentzone-october-2025.html

https://www.analog.com/en/resources/analog-dialogue/studentzone/studentzone-november-2025.html

are parts one and two of an article on W B oscillators.

If you want a circuit which is simple and a sine wave with around 2 to 3 % THD is tolerable, use back to back diodes as in the second link.

I have a Philips audio signal generator with a switch to select between low distortion mode using a thermistor, and fast settling mode using diodes.

[Terry Bites]

We should all honour our inventors and discoverers with their proper noun.
Use capital letters and correct spellings.

Schottky, Ohm, Siemens, Watt, Henry, Zener, Coulomb, Thévenin, Karnaugh, Bode, Miller, Hertz, Boole,  etc etc.