Wein Bridge

This circuit produces an extremely low distortion sine-wave, in spite of the non- linear devices used for amplitude limiting (D1 and D2). The reason is first that distortion (harmonics) are fed to the minus input of the opamp with far less loss than to the plus input, severely attenuating them. Second, a Wien bridge oscillator requires a gain of exactly 3.00. No more and no less. For lowest distortion, calculate the minimum and maximum available gain to just above and just below 3.00. In other words, use as little amplitude control as possible.

Transformer T1 reduces the mains to an appropriate voltage and provides isolation for safety. CR1 and CR2 provide half-wave rectification of T1's secondary voltage. The positive, pulsed DC voltage at CR1's cathode is filtered by capacitor C2, and applied to the input of voltage regulator VR1. VR1 provides +12 volts for the rest of the circuit.

This is an image Schematic. No Description available.

This circuit produces an extremely low distortion sine wave, in spite of the non- linear devices used for amplitude limiting (D1 and D2). The reason is first that distortion (harmonics) is fed to the minus input of the opamp with far less loss than to the plus input, severely attenuating them.