In circuits 1, 2, and 3, the LM386 inputs are connected directly across the tank circuit and use the LM386 as an RF envelope detector. Circuit 4, with its relatively large value coupling capacitor, ...

The points A and B on the circuits with LM386 can be used to stop the oscillators with elements having open collectors or open drains; for the NE555, the reset input serves the same function.

The Wien bridge itself goes back to the 1890s when it was developed for impedance measurements, and its use in the feedback circuits of vacuum tube oscillators dates back to the 1930s.

Find The LM386 Audio Amplifier Circuit, Datasheet and Pinout From ElectroSchematics. Plus, Find Helpful Diagrams and Resources. Visit To Learn More.

For [Grug Huler], this was one of those “just for funsies” projects stemming from a data sheet example circuit showing a bulb-stabilized LM386 audio oscillator.