The Lightbulb that Lit the Way to HP

On July 27, 1938, while working as a researcher at Stanford, Bill Hewlett had an idea that would revolutionize oscillator technology and lead directly to the founding of Hewlett-Packard. Engineers had long sought a way to create a resistor whose resistance could vary to match a wide range of signals. Bill realized that when a light bulb converted electricity to heat and light proportionate to the power it received, it was basically acting as a variable resistor. He integrated a socket and a fifteen-watt bulb into his oscillator prototype, and wound up with an instrument comparable to the best oscillators on the market for a fraction of the production cost. The breakthrough would be applied to Hewlett-Packard’s first product, the 200A oscillator, and would continue to be key to Hewlett-Packard oscillators for decades. One historian recalled, “what Hewlett accomplished that July day remains one of the most clever bits of practical invention in technology history.”