Vintage analog computer kits
By James Grahame
The Heath company (of Heathkit radio, robot and computer fame) began offering "inexpensive electronic analog computer" kits in 1956. Prices ranged from $495 to $945 - an enormous sum in those days. The computer was "programmed" using a bank of 30 high-precision potentiometer knobs and a visually impressive patch panel covered with plug points and switches - there was no digital circuitry at all.
Odd as it may seem, an analog electronic computer has a few advantages over its digital counterparts. Analog electronic calculations are performed almost instantaneously using a network of operational amplifiers that modify continuously variable current. And - in the not-so-distant past - purpose-built analog computing circuits could be built less expensively than comparable digital systems. One classic example of an analog computer in action is the Magnavox Odyssey video game console from 1971, which plays mind-numbingly simple Pong-like games without a microprocessor.
Alas, analog electronic computers work best as single-purpose circuits. They're cumbersome and complicated to re-patch and can't match the level of precision offered by even a simple digital calculator (it's hard to get more than 3 or 4 digits of precision). Still, I suspect that the recent arrival of programmable analog chips may signal the rebirth of interest in analog computing.
"This is a highly flexible and accurate analog computer, designed to fill requirements not presently met by any commercial computer. Ideal for solving practical problems in industry, and equally valuable for research, or instructional demonstration, in colleges or universities. Because it is a kit, and the labor and overhead costs found in present day computers are eliminated, the Heath Computer can be obtained for use in situations where a computer was ruled out in the past because of cost."