How Does an Audio Oscillator Work?


Quick Answer

An audio oscillator works by altering resistance over an electric circuit and turning electricity into a pure sound, explains a resource on the Ohio University website. William Hewlett patented and designed a better audio oscillator when he was a graduate student at Stanford University in 1938. The model 200A oscillator was Hewlett Packard's first product sold to businesses and consumers.

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How Does an Audio Oscillator Work?
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Full Answer

Hewlett's improvement involved reducing negative feedback by inserting a low-cost light bulb. The improvement canceled unwanted variations in the sound as the light bulb fluctuated in intensity. When the light bulb canceled negative feedback, the oscillator maintained a nearly constant output.

Hewlett's original resistance-tuned oscillator worked from a range 35 cycles per second up to 35,000 cycles per second in three different ranges. Thanks to the small light bulb, the harmonic variance was less than 0.5 percent over the entire audio spectrum of the instrument.

Original oscillators used resistors and vacuum tubes to transmit electricity and turn power into pure sound. Oscillators were used to produce telephones, radios, stereos and other audio equipment by creating specific frequencies. Hewlett's design improved upon the coil-condenser version of oscillators and made a product with resistors and capacitors that determined the frequency emitted by the device. Hewlett pioneered portable audio oscillators and created an entirely new industry of home electronics based on the compact nature of the 200A oscillator.

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