In 1963, Friden developed the first solid state electronic calculator. It went on sale about 1 year later. The circuitry inside its massive, aluminum chassis mostly consists of discrete PNP germanium diodes and transistors. The display uses a 5″ green phosphor electrostatic-deflection CRT screen. The outward case is beautifully designed and is one of the best looking machines I’ve ever seen.
A multi-register stack is displayed on the screen with each line holding up to 13 characters. A memory register also exists, but its value is not displayed until it’s recalled. The calculator was the first to use Reverse Polish Notation (RPN), meaning values are entered into the stack before the operator is pressed.
Here’s a brief review of the machine, its history and a look inside the unit: