OUR EXPERT
Mike Bedford is fascinated to see how analogue computers of the ’60s and ’70s can demonstrate chaotic systems, even though chaos theory wasn’t popularised until much later.
As we saw last month, although analogue computers might seem ancient, they gave digital computers a run for their money until the early ’80s. Their particular strength was solving differential equations, so they were used for simulation, primarily in scientific and technical applications.
In the first part of our exposé of electronic analogue computers, we turned to emulation to see how they worked and how they were used. Specifically, we emulated a simple analogue machine – not too dissimilar from the ones that were used in education – but that approach limited the types of problem that could be solved. So, now we’re going to see how to emulate a more sophisticated machine, to allow us to use analogue techniques to solve some more complicated and more interesting problems.
And finally, for those who want to try out some real analogue hardware, as opposed to emulating analogue computers digitally, we’ll introduce some exercises to help you better understand the underlying electronics, and even point you towards a real open hardware machine that you can buy.
A different approach
The emulator that we used last month was built using the circuit simulator, and this served to provide some insight into analogue computing hardware. The same approach could have been extended to create a larger machine with more potentiometers, summers and integrators. But while this would have allowed problems involving more differential equations to be solved, it would still have been limited. In particular, while it allowed a variable to be multiplied by a constant – this being the function of a potentiometer – it couldn’t multiply two variables. And while lots of problems, like the examples in part one, don’tto add a multiplier, but while the circuits for potentiometers, summers and integrators are pretty simple, the same isn’t true of an analogue multiplier. If you’re really keen, you could research the subject and
