Planet Sinclair, by Chris Owen.

The Web’s biggest Sinclair-related archive:

Executive Calculator
“…The Sinclair Executive was the world’s first pocket calculator.
The advert described it as being “as thick as a cigarette packet”, reflecting Clive Sinclair’s stated belief that One must always bear a packet of cigarettes in mind as the ideal size.

…battery life was only a few hours and the machine could be physically dangerous. If it was left on, the batteries had a nasty habit of exploding and blowing the machine to bits.”.

C5 electric car
“Possibly Sinclair’s most famous product (albeit for quite the wrong reasons).

…Exactly a decade before the C5 fiasco, Sinclair was nearly brought down by another disastrous product: The Black Watch.”.