Bowmar was a small company specialising in high technology components for the space programmes and produced a hand-held calculator as a demonstration device for its Light Emitting Diode (LED) displays - “funny red numbers that are almost illegible”. So good was the reception to the Bowmar 901B calculator, fondly called the Bowmar Brain, that in September 1971 it moved into large scale calculator production. This model (the 901B) was also produced for other companies including Craig (model 4501) and Commodore (C110).

The Bowmar 901B had 4 functions - add, subtract, multiply and divide - and that was all it does. The can only display up to 8 digits. It sold for about USD $200.

By 1974, Bowmar was the largest manufacturer of hand-held calculators in the world. Bowmar’s total sales increased from $3m in 1971 to $64m in 1973.

With the dramatic fall in calculator prices in the mid-1970s, Bowmar decided that it needed to manufacture its own integrated circuits to remain competitive and in 1974 invested in a semiconductor plant. However, prices continued to plummet and Bowmar had to file for bankruptcy protection early in 1975.