Comdyna GP-6

Comdyna GP-6 analog computer was designed to simulate dynamic systems by implementing electrical circuits that are governed by the same set of differential equations as the system under study. A number of features, such as variable time scaling and repetitive mode operation, are built into the unit to make the simulation easily accessible to the user. In addition to having built-in op amps, resistors, capacitors, and

potentiometers, the GP-6 has an overload indicator that signals when an amplifier is saturated, a mode for accurately setting potentiometer values, a digital voltmeter for measuring external signals such as sensor outputs, a capacitor shorting feature for zeroing integrators, complete banana plug access, current limiting to protect circuitry, and convenient ground and ±10V references.

The analog computer contains 8 op amps. Amplifiers 1-4 have a rather complicated configuration of resistors and switches connected to their inputs at node SJ. Amplifiers 5 and 6 can only be used as gains and summing nodes, since they are not connected to capacitors. Amplifiers 7 and 8 are internally configured as inverters. The analog computer provides 8 10-turn potentiometers, which can be used in conjunction with the op amps and fixed circuit elements to achieve virtually any desired gain. Potentiometers 1-6 are internally grounded on one side. Potentiometers 7 and 8 are floating, but may be grounded by connecting a jumper to the ground terminals directly below them on the panel. Turning the knobs labeled “1“through” 8 can set the potentiometer values. The computer offers an elegant way of setting potentiometer gains.