The Soverign was produced from 1976 and named to commemorate the Queen's Silver Jubilee. It was an attempt to move up in the market and Sinclair designer John Pemberton won a design council award for it.
It was small, slim, made from pressed steel and available in a range of finishes.There was black painted, satin chrome finish and silver or gold plated. A small number of solid gold models were also produced.
A chrome plated model cost about £30 in 1976.
It's downfall however was that it still used power-hungry LEDs when cheap LCD displays were becoming the norm whose batteries lasted for months. Soon Sinclair was selling them at a loss.
Display : 8 digit Red LED
Functions : +, -, *, /, %, memory, square root, square.
Batteries : 2 X watch batteries (2.5V)
Integrated circuit : Mostek MK50321N
Black painted model with case
Black painted model with higher quality case
Note the Ford logo embossed near the bottom
A black model with the Plessey logo embossed on the case
A gold plated version, costing £60 in 1976.
Chrome-plated or possibly silver-plated version.