The Smallest Analog Computer Ever Made?! By James Grahame From
the early 1960s brochure: "Donner's Model 3500 is a full-fledged
analog computer weighing just 28 lbs. Designed for engineers,
educators and scientists, it can be used to study almost any
physical system that can be described by differential equations.
It can be operated on desk tops and benches by anyone who can
run a slide rule. The standard 3500 contains 10 amplifiers,
stabilized or unstabilized as the user chooses. The computer
performs accurately with 1% or 0.1% computing components, and is
furnished ready-to-work for $1850, depending upon specific
equipment desired." Fast forward 50 years, and I'd much rather
have a Macbook. It's astounding to realize just how far we've
come in the past half century; the Donner 3500 used vacuum tubes
and was anything but simple to use. These days, you could create
a comparable analog function generator using a variety of solid-
state op amps and buffers that cost only a few cents each.