So I have been trying to get this circuit to work with no success. I started with R5 using 200 ohms and finally concluded that that was just too small of a resistance. So I am opening this project for general comment. Ideas? Suggestions?
to start off I adjusted R5 to 600Ω/300Ω for a gain of two.
Your circuit will work with a power amplifier like an LM386, it is in its datasheet.
For a low power opamp, a low power incandescent light bulb might not be found.
The gain for a Wien Bridge oscillator must be 3.
Pin 5 of the opamp connects to nothing.
R1a and R1b do not connect together.
There is no supply voltage.
Now R5 does not connect to pin 7 because it is cut away and instead it wrongly connects to pin 5.
Then when fixed and the gain is set to 3 or a little more does the oscillator work with no AGC because the light bulb needs too much current?
Can you see and hear and see on a scope the crossover distortion and hiss from the lousy old LM358?
That should work but the output may vary between clipped and nothing with temperature changes. The non-linearity in the signal diodes in my circuit stabilize the amount of feedback and avoid that problem..
This I understand. I am hoping to come up with my own design. With the brain fog I no longer grok in fullness wiring that was once simple for me. Any Robert Heinlein fans here?
I had been wondering about this idea for some time, so I thought I'd try it on SPICE to see how well it works.
This is the Linsley-Hood two-op-amp Wien Bridge, made with rail-to-rail op-amps. The final output (from U2) is a clipped sinewave, but that output goes into the Wien network then it appears band-pass filtered, out of phase and at half the amplitude at the output of U1.
The band-pass filtering removes quite a lot of the distortion, so that the U1 output has 3rd harmonic distortion at 50dB below the fundamental (0.3%).
[Edit] SPICE seems to require me to add a bit of noise to make it start up - hence the Gaussian noise source.