[TopHand]

The first computer I ever owned was an analog computer from Edmund Scientific. It was fundamentally an electronic slide rule. It had a meter that swung from a negative value to a positive value. The operator adjusted some potentiometers so that the meter was nulled. The output was read from the numbers pointed to by the knobs on the pots. At least that is the way I remember it working. I don't recall how exactly the equation was entered, but I think there were some pots for that too.

As far as building your own analog computer, look at op amps. They're called that because they perform mathematical operations, such as summing, multiplying, and integration. Of course they do the inverse operations as well.

[sansnomme]

With two op amps you can build a neural network. (Or at least a single perceptron)

https://www.nutsvolts.com/magazine/article/the_perceptron_ci...