Analog computers use continuous physical magnitudes to symbolize quantitative statistics. At first they represented portions with mechanical components (see differential analyzer and integrator), however after World War II voltages had been used; with the aid of the Sixties digital computer systems had in large part replaced them. https://files.tips/extension/fb2 Nonetheless, analog computer systems, and some hybrid virtual-analog systems, endured in use via the Nineteen Sixties in responsibilities including aircraft and spaceflight simulation.