Enterprise (1977-78)
This chrome-coloured calculator was launched during a difficult period for Sinclair Radionics, named after the UK’s National Enterprise Board (NEB), which was financially supporting the company at the time. It featured bright red LED digits—unusually large for a pocket calculator—enhanced by magnifying lenses. Marketed as easy to use, it reflected customer research showing that users preferred visible, well-spaced displays over newer low-power LCDs. Despite these efforts, it struggled to compete and was ultimately sold at a loss.
Released a year after the Enterprise, this black calculator added programmable features and came packaged with a comprehensive three-volume library of over 300 ready-made routines. Users could store up to 79 steps per program, using conditional and branching instructions for basic customisation. Though still modest compared to competing devices, it marked Sinclair’s third and most advanced programmable calculator. A curious design feature required the entire front panel to be removed to access the battery—an unusual solution to a common problem.