An audio oscillator is an instrument that generates one pure tone or frequency at a time. Through the years, HP oscillators were used to design, produce and maintain telephones, stereos, radios and other audio equipment.
In 1938, when the sound engineer for the movie Fantasia from the Walt Disney Studios saw the Model 200A audio oscillator in action, he asked Bill Hewlett to make some modifications to it, and the Model 200B was born. Disney ordered eight of the Model 200B at $71.50 each.
Disney engineers used HP 200B oscillators to test the various channels, recording equipment and speaker systems in the 12 specially equipped theaters that showed Fantasia in 1940.
This particular 200B was produced for the Naval Research Laboratories during World War II.