Machine Unit

THE ANALOG THING's machine unit is the voltage interval in which the device represents values. This interval is -10V to +10V. THAT users are expected to scale their programs to fit into the interval [-1,+1], which THAT represents in its -10V to +10V machine unit.

To understand the need for these scale conversions, consider that users want to model values at any scale while THAT is limited to its modest physical boundaries. Modeling the dynamics of the global human population (currently around 7.9 Billion) should obviously not require 7.9 Billion volts. The population value needs to be scaled. As a convention, analog computer models are scaled to the model unit [-1,+1]. The global population might, for example, be represented as 0.79. In its machine unit, THAT would then represent this value as 7.9V.

Good model scaling results in programs that use as much of the machine unit as possible ​without exceeding it. You understand the reasons for this if you understand that weighing cooking ingredients on scales intended for trucks or weighing a truck on a kitchen scale would not give very useful results.

Using the -10V to +10V range as the machine unit is an engineering choice and a convention. It happens to be a very good choice because it allows for easy conversions in the decimal number system, it can be handled very precisely using affordable electronic components, and it is perfectly safe for humans.

When any value in a program exceeds the machine unit, the red OL (overload) LED lights up. This is not dangerous for the device. However, in this condition, THAT will likely "clip" any excess voltages, and the values in question will not be computationally correct.

Output signals available via the RCA (or "chinch") jacks on the device's backside are not in the machine unit. Instead, they are attenuated to smaller audio signal levels to conveniently be read into software oscilloscopes via sound card interfaces.