How did the Differential Analyzer solve differential equations?

The differential analyzer, developed by Vannevar Bush at the Massachusetts Institute of Technology in the 1930s, was an electromechanical analog computer designed to solve differential equations by representing variables through physical shaft motion.12

The machine solved these equations through the following mechanical processes:

• Basic Arithmetic: Addition and multiplication were performed by feeding values into a complex system of gears.2
• Integration: This core operation was achieved using a knife-edged wheel that rotated at a variable radius on a circular table.2
• Interconnection: Multiple mechanical integrators, consisting of disks, wheels, and shafts, were interconnected to model and solve specific sets of differential equations.12

While the device provided practical, approximate solutions for complex physics and engineering problems, it required significant manual setup and was eventually superseded by the digital computer in the 1950s.12