Birthplace of Silicon Valley (1939)

 

David Packard and Bill Hewlett founded their company Hewlett-Packard in a Palo Alto, California garage. Their first product, the HP 200A Audio Oscillator, rapidly became a popular piece of test equipment for engineers. Walt Disney Pictures ordered eight of the 200B model to test recording equipment and speaker systems for the 12 specially equipped theatres that showed the movie “Fantasia” in 1940. In 1939, Hewlett completed his EE masters thesis at Stanford. His thesis project was a variation of the Wien bridge oscillator, in which he used the negative differential resistance of an incandescent lamp to act as a parasitic impedance in the feedback loop. This ensured that the oscillator operated just at unity gain, and thus produced steady, low-distortion output. This was a really clever and elegant hack — many oscillators of the time did not produce steady oscillations, but instead fed a pulse stream (sometimes just a rectified mains signal) to an RLC tank circuit with a large Q — so the output was a series of decaying oscillation patterns with modulation at this pulse frequency. Oscillators which did produce steady output were large and expensive. Hewlett replaced the complex control systems of these with a simple light bulb. HP’s first product, the HP200A bench oscillator, was based on Hewlett’s thesis design, optimized for manufacturing in the now famous garage in Silicon Valley.