Sinclair Advert - December 1974

It's not uncommon for adverts for microcomputers or electronics - especially early on - to look somewhat "hand made", but this would win an award, if there was one, for the most poorly laid out, looking as it does like blocks of words had been printed, cut out, and then scattered semi-randomly where they were roughly supposed to go.

The double-page spread of adverts for two of Sinclair's calculators originates from Gladstone Electronics of Canada's 1975 Mail Order and Retail Store Catalogue No. 14, published towards the end of 1974.

It shows both the Sinclair Cambridge, retailing for C$44.95, or around £330 in 2026 money, and the higher-end Sinclair Scientific, for C$139.95, which is about £1,010 now.

In common with much of Sinclair's output at the time these were kit prices, although ready-made versions were also available at a 40% premium in the case of the Scientific.

The Cambridge was released in the late summer of 1973, with the company having launched its first calculator, the Executive, the year before.

Prior to that Sinclair - or more correctly Sinclair Radionics - had been mostly famous for its hi-fi kits and components, but the Executive and its various follow-ups were perhaps the company's true mass-market breakthrough and became hugely successful, propelling Sinclair to number one in the UK calculator market^[1].

This was not so much because of any technical prowess, as most of Sinclair's calculators were made with cheap components and we often slow and not necessarily that accurate, but because those cheap components allowed Sinclair to sell its machines for much less than the competition.

Not only that, but the Executive was also the slimmest calculator on the market when it was first launched.

A later programmable model of the Cambridge, which was sold by Tandy/Radio Shack as its EC-4001 model, used an eight-digital red LED display manufacturerd by National Semiconductor, as well as National Semiconductors' integrated circuits^[2].

This relationship would survive the Calculator Wars of the mid 1970s, which all but destroyed the calculator market as well as several of the companies in it, when Sinclair launched its first computer - the MK14 kit - in 1978.

This calculator-like microcomputer kit was based on NatSemi's SC/MP, or "Scamp" processor, as well as probably the same eight-digit calculator display of its forbears.