Hello, i made a wien oscillator with a 741 op amp the problem is it outputs a very narrow and cut off signal that is almost like a triangle wave, you can see it attached in the files.
I have zero idea why it doesnt output a normal sine wave. Im using 10k resistors and 10nf capacitors for the filters loop, a 47k trimmer as the gain loop paired with another potentiometer used as a gain adjuster.

 

The 741 is a very old IC. There are more modern chips available with wider bandwidth and frequency. Try a TL071, dirt cheap and so much better than a 741.

 

Hello,

When using fixed gain for a wienbridge oscillator, distortion will happen.
You will need an amplitude stabilasation circuit.
The attached PDF files will show you techniques for generating sine waves.

Bertus

 

The TL071 is pin compatible, as are many others, as the 741 set the benchmark all those years ago.

 

No schematic shown. How to discuss the circuit?

 

Post your schematic.

 

This is the schematic

 

Simulation:

ADDED:
With your values of resistors:

 

Note that the amplitude and distortion of that circuit is very sensitive to the op amp gain as determined by R2 and R3.
If you reduce the value of R2 in your real circuit, it should reduce the amplitude and distortion.
You may want to replace that resistor with a 100kΩ pot.

Typically such a circuit use some sort of AGC in the feedback to stabilize the amplitude without requiring any tweaking.

 

A wein bridge oscillator circuit is not stable; that is, amplitude stable. It makes a perfect sinewave at a constant output amplitude ***only** with theoretically perfect resistors than you can not purchase. As above, a successful circuit always has some form of feedback based on the peak, average, or RMS value of the output waveform. Search for Wein bridge oscillator circuits to see hundreds of examples.

ak

 

The clipped waveform shown is differentiated as though it has an output coupling capacitor value that is too small and is feeding a load.
I simulated what I am talking about but my Sim software does not have an antique 741 opamp:

 

The clipped waveform shown is differentiated as though it has an output coupling capacitor value that is too small and is feeding a load.
I simulated what I am talking about but my Sim software does not have an antique 741 opamp:

So you suggest adding stronger capacitors in the filter loop?

 

Hello,

It is not the filter capacitors, but the gain control.
Have a look at the PDF's I posted in post #3.

Bertus

 

Hello,

It is not the filter capacitors, but the gain control.
Have a look at the PDF's I posted in post #3.

Bertus

Nothing here helped, i looked up that it could be the power supply since mine is really shitty, i post the model here.
EVENTEK KPS3010D

 

Hello,

Did you have a look at the AGC circuits?




Bertus

 

Hello,

Did you have a look at the AGC circuits?
View attachment 243121

View attachment 243122

Bertus

Yes but i dont have a jfet, when i plugged in the diodes for automatic gain control it started doing wierd spikes at the start of the wave signal

 

The highpass and lowpass filters are fine.
I suggested that the horrible waveform is caused by a capacitor-coupled load that you did not show that has its coupling capacitor having a value that is much too low. Your load resistance that also was not shown might be too low.

The basic Wien-Bridge oscillator you show has nothing to control its output level so the output of the opamp is clipping and is producing almost squarewaves. Then the very low value of the unseen output coupling capacitor that I added blocks the low sinewave frequency but passes the high frequency distortion harmonics.

 

Diodes? Your schematic is missing the diodes that you talk about. Where are they on the schematic?
Please add the load, its coupling capacitor and the diodes to your schematic.

 

This is the new schematic i tried, it gives a wierd spiky wave signal

 

Hello,

The wiki also shows a circuit using diodes for amplitude regulation:

https://en.wikipedia.org/wiki/Wien_bridge_oscillator

Bertus