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Electronic Analog Computers

While these components are not all that are found on real electronic analog computers (those few that still remain), they are the primary ones. We will denote them with the commonly used symbols shown in Figure 8.

Figure 8:  Symbols used for Computing Components

Notice that we haven't specified what gain factors are on the inputs of the summers or integrators. In practice, we usually have a small variety of gains available; usually 1, 4 and 10. The gain we use is noted inside the symbol beside the input in question. For the example in the next section, we use only gain 1 inputs, so we'll just leave them off completely.

Also notice the input for initial conditions shown at the top of the integrator. This is a common convenience feature. From the equation give for integration, it is clear that we can actually add the initial condition in a summer in a stage following the integrator. However, most real computers provide initial condition inputs on the integrators.

Brian L. Stuart
Fri Mar 14 11:57:03 CST 1997