Electronics/Op-Amps/Non Linear Configurations/Oscillator/Wien bridge Oscillator

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Wien bridge Oscillator[edit]

A Wien bridge oscillator is a type of electronic oscillator that generates sine waves. It can generate a large range of frequencies. The circuit is based on an electrical network originally developed by Max Wien in 1891. The bridge comprises four resistors and two capacitors. It can also be viewed as a positive feedback system combined with a bandpass filter. Wien did not have a means of developing electronic gain so a workable oscillator could not be realized.

The modern circuit is derived from William Hewlett's 1939 Stanford University master's degree thesis. Hewlett, along with David Packard co-founded Hewlett-Packard. Their first product was the HP 200A, a precision sine wave oscillator based on the Wien bridge. The 200A was one of the first instruments to produce such low distortion.


Classic Wien bridge oscillator

The frequency of oscillation is given by:

f = \frac{1}{2 \pi R C}