The Sinclair Wrist Calculator was a wrist-worn calculator produced by
Sinclair Instrument
Sinclair Research Ltd is a British consumer electronics company founded by Clive Sinclair in Cambridge. It was originally incorporated in 1973 as Westminster Mail Order Ltd, renamed Sinclair Instrument Ltd, then Science of Cambridge Ltd, then ...
and introduced in 1977.
History
The Wrist Calculator was launched in February 1977 by Sinclair Instrument, a company established in parallel to
Sinclair Radionics
Sinclair Radionics Ltd was a company founded by Sir Clive Sinclair in Cambridge, England which developed hi-fi products, radios, calculators and scientific instruments.
History
After raising funds to start the business by writing articles ...
when the latter started to encounter financial difficulties.
It was only available as a mail-order kit, and cost around .
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...
, but most went unsold and were returned to Sinclair.[ It was described as an "utter dud" and "impossible-to-build" by the journal ''International Design''.]
Design
The design used 10 keys, with a three-position switch
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type ...
to select the correct function. The switch was held to the left to access the functions to the left above the keys, and to the right to get the functions to the right above the keys. In the centre position it would enter the numbers on the keys.algebraic logic
In mathematical logic, algebraic logic is the reasoning obtained by manipulating equations with free variables.
What is now usually called classical algebraic logic focuses on the identification and algebraic description of models appropriate fo ...
, as opposed to the reverse Polish notation
Reverse Polish notation (RPN), also known as reverse Łukasiewicz notation, Polish postfix notation or simply postfix notation, is a mathematical notation in which operators ''follow'' their operands, in contrast to Polish notation (PN), in whi ...
employed on some Sinclair calculators.[
]
References
{{Sinclair calculators
Sinclair calculators