I've been working on a Wein-Bridge oscillator off and on for the last few days as a hobby since I haven't done analog design for decades but used to enjoy it in the early days of my career. I had difficulty getting the amplitude to be stable without the op amp going into saturation with the resulting high distortion. I tried using the light bulb approach to stabilizing the amplitude and it worked except that there was a small 5Hz amplitude modulation on the output that I could not figure out how to eliminate. At that low frequency it had to be something to do with either the light bulb or heating in the op amp due to having to drive the fairly low impedance in the feedback loop. I tried using a thermistor but it was way too sensitive to slight room temperature variations. Finally I saw this video and tried the diode clamp approach. That worked great! I can't measure the distortion but the sine wave looks perfect on the scope except for a very slight aberration when the diodes turn on and I can set the output amplitude somewhat by varying the resistor in series with the diodes.
I've been working on a Wein-Bridge oscillator off and on for the last few days as a hobby since I haven't done analog design for decades but used to enjoy it in the early days of my career. I had difficulty getting the amplitude to be stable without the op amp going into saturation with the resulting high distortion. I tried using the light bulb approach to stabilizing the amplitude and it worked except that there was a small 5Hz amplitude modulation on the output that I could not figure out how to eliminate. At that low frequency it had to be something to do with either the light bulb or heating in the op amp due to having to drive the fairly low impedance in the feedback loop. I tried using a thermistor but it was way too sensitive to slight room temperature variations. Finally I saw this video and tried the diode clamp approach. That worked great! I can't measure the distortion but the sine wave looks perfect on the scope except for a very slight aberration when the diodes turn on and I can set the output amplitude somewhat by varying the resistor in series with the diodes.
very clear and concise explanation. thank you!
What is the value of 2R1 when R1 is a tungsten lamp? Thanks
Great tutorial !....cheers.
This is a very good class. Thanks very much!
It Helped me a lot, thanks
great video
So helpful!
Great video, just the script could be slightly larger to be legible !
words are quite large please write a further smaller. :)
You are excellent, but the words are too small, girl