1972
Clive Sinclair introduces the first pocket calculator

Clive Sinclair is the first (August 1972) to bring a pocket calculator - the size of a package of cigarettes - based on the Texas Instruments GLS 1802, only the basic calculations were possible though. Pricing: expensive but lower than others: 79 UK pounds. Power consumption is compared to other calculators extremely low due to a smart power switching technique. The reason why this calculator has a small footprint.

(Texas Instruments brought out the types TI2500, 3000, 3500) but they were still very expensive. All basic functions ( + - / : *) and a percentage key were present. Numbers were displayed by a special kind of LED's, at the same time the reason for high battery consumption. Rechargeable batteries only existed in laboratories yet.