Tools for the mind: Sinclair Scientific calculator
My friend Al brought his Sinclair for me to test. A set of new batteries and the device glowed away.
“An ingenious aspect of the design which showed Sinclair’s inventiveness was that the machine made use of what was originally a 4-function calculator chip. Sinclair realised that by using RPN and allowing a reduced precision of 4 or 5 significant figures displayed in scientific notation, the algorithms for scientific functions could be redesigned and compacted to fit in the same programmable space on the chip. This allowed Sinclair to adapt the relatively low-cost processor and produce an ‘electronic slide rule’ that fitted easily in a shirt pocket, at a price that even impecunious students could afford.”
My Sinclair Oxford 300 replaced my slide rule in 1975.