Term of the Moment
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Definition: analog computer
A device that processes infinitely varying signals, such as voltage or frequencies. A thermometer is a simple analog computer. As the temperature varies, the mercury moves correspondingly. A slide rule is another example. Although special-purpose, complex analog computers are built, almost all computers are digital. Digital methods provide programming flexibility. See digital computer.
The Antikythera Analog Computer
Estimated to be at least 2,000 years old and discovered in 1901, this is the largest gear (5.5") in the analog device found in the Antikythera Roman-era shipwreck. It modeled the movement of celestial bodies in order to calculate the position of the sun and moon at various times. (Image courtesy of Creative Commons license 2.5 Generic, http://creativecommons.org/licenses/by/2.5.)