Low Distortion Audio Sine Wave Oscillator Circuit Diagram

Generates very low-distortion sine waves up to 1V RMS

No thermistors required - No settling time

Circuit diagram

Parts:

Comments:

Producing low-distortion sine waves, this oscillator operates across a range of 16 to 22 kHz. The circuit is based on concepts from earlier designs presented in Wireless World - Roger Rosen's "Phase-Shifting Oscillator”, February 1982, pages 38-41, and J. L. Linsley Hood’s "Wien-Bridge Oscillator with low harmonic distortion" from May 1981, pages 51-53.

This design incorporates the simplicity of the Rosen's circuit but avoids the use of a thermistor. Instead, oscillator stability is controlled using a common photo-resistor, driven by a red LED, as suggested in the Linsley Hood article.

There is no settling time when the oscillator’s frequency is changed, and the output waveform does not exhibit any bouncing. The implementation of an expensive and sometimes difficult to obtain thermistor has been avoided.

Technical data:

Notes:

This circuit was awarded publication in ELECTRONICS WORLD "Circuit Ideas", February 2003, page 38.