The differential analyser is a mechanical analogue computer designed to solve differential equations by integration, using wheel-and-disc mechanisms to perform the integration.[1] It was one of the first advanced computing devices to be used operationally.[2] The original machines could not add, but then it was noticed that if the two wheels of a rear differential are turned, the drive shaft will compute the average of the left and right wheels. Addition and subtraction are then achieved by using a simple gear ratio of 1:2; the gear ratio provides multiplication by two, and multiplying the average of two values by two gives their sum. Multiplication is just a special case of integration, namely integrating a constant function.[3]
- ^ Irwin, William (July 2009). "The Differential Analyser Explained". Auckland Meccano Guild. Archived from the original on 2018-11-24. Retrieved 2010-07-21.
{{cite web}}: CS1 maint: bot: original URL status unknown (link) Archived - ^ "Invention of the modern computer". Encyclopædia Britannica. www.britannica.com. Retrieved 2010-07-26.
- ^ John von Neumann, The Computer and the Brain, Part 1, p.3, Yale University Press, The Silliman Memorial Lectures Series, 1958