Electronic Associates Inc. Model 680 Scientific Computing System

UvA Computer Museum catalogue nr 93.56

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Our EAI 680 has been part of a hybrid system; unfortunately the digital part has not survived. Nevertheless the 680 is a complete analog system equipped with

• 120 analog modules including integrators, summer/amplifiers, limiters, function generators, multipliers, comparators and a/d convertors. These units are accessible through the removable patch panel (right).
• A control & logic panel (upper part of the patch panel) containing various gates, clocks, pulse generators, relays and bcd counters.
• 100 servo-controllable coefficient potentiometers, plus a number of manually adjustable units on the front panel (left).
• A keyboard for entering coefficients and for general control.
• Lighted pushbuttons for reading and defining the state of the logical units.
• A digital voltmeter with a large decimal display (bottom left).

The results of the computations can be displayed on a plotter or on a large screen oscilloscope (not shown; we don't have the original EAI units).
Our 680 machine, dating from 1968, is fully functional. This is illustrated by the picture below, where the machine is shown while solving the differential equation of a damped pendulum.