Analog computer

For the Atari 8-bit computer magazine, see ANALOG Computing.

A page from the Bombardier's Information File (BIF) that describes the components and controls of the Norden bombsight. It was a highly sophisticated optical/mechanical analog computer used by the United States Army Air Force during World War II, the Korean War, and the Vietnam War to aid the pilot of a bomber aircraft in dropping bombs accurately.
TR-10 desktop analog computer of the late 1960s and early 1970s

An analog computer or analogue computer is a type of computation machine (computer) that uses physical phenomena such as electrical, mechanical, or hydraulic quantities behaving according to the mathematical principles in question (analog signals) to model the problem being solved. In contrast, digital computers represent varying quantities symbolically and by discrete values of both time and amplitude (digital signals).

Analog computers can have a very wide range of complexity. Slide rules and nomograms are the simplest, while naval gunfire control computers and large hybrid digital/analog computers were among the most complicated.[1] Complex mechanisms for process control and protective relays used analog computation to perform control and protective functions.

Analog computers were widely used in scientific and industrial applications even after the advent of digital computers, because at the time they were typically much faster, but they started to become obsolete as early as the 1950s and 1960s, although they remained in use in some specific applications, such as aircraft flight simulators, the flight computer in aircraft, and for teaching control systems in universities. Perhaps the most relatable example of analog computers are mechanical watches where the continuous and periodic rotation of interlinked gears drives the second, minute and hour needles in the clock. More complex applications, such as aircraft flight simulators and synthetic-aperture radar, remained the domain of analog computing (and hybrid computing) well into the 1980s, since digital computers were insufficient for the task.[2]

  1. ^ Gallagher, Sean (17 March 2014). "Gears of war: When mechanical analog computers ruled the waves". ARS Technica. Archived from the original on 8 September 2018. Retrieved 14 June 2017.
  2. ^ Johnston, Sean F. (2006). Holographic Visions: A History of New Science. OUP Oxford. p. 90. ISBN 978-0191513886.