Date of intro: sep-1972,
Classification: / Documentation / Article,
Related with: TEXAS INSTRUMENTS_parts(E): TMS1802NC (CalcChip),
Serie-members: (Docu_Articles): 197209: The Wireless World Desk Calculator (part-1) (Part-1); (Docu_Articles): 197210: The Wireless World Desk Calculator (part-2) (Part-2),
Publisher-1: WIRELESS WORLD, Publisher-2: ALEXANDER Roger / CRANK Brian,
Info: The article describes the development, design, construction, and operation of the WIRELESS WORLD Desk Calculator, created through cooperation between WIRELESS WORLD and ADVANCE ELECTRONICS Ltd. The goal was to produce a relatively inexpensive electronic calculator that could be assembled from a kit costing £39.25
The article first explains the evolution of calculators.
Early mechanical calculators were large, noisy, expensive, and required maintenance.
Early electronic calculators were also expensive because they contained many separate components.
The introduction of integrated circuits made calculators smaller and cheaper.
A major breakthrough came with MOS large-scale integration, which allowed the main arithmetic, control, and memory functions to be combined on a single chip.
At the heart of the Wireless World calculator is the TEXAS INSTRUMENTS: TMS1802NC chip.
This small silicon chip contains more than 6.000 transistors and performs the calculator's arithmetic, control, and storage functions.
The calculator can add, subtract, multiply and divide, as well as perform chain calculations, calculations with constants, and automatic squaring.
The results are displayed using nine gallium-arsenide LED displays.
The calculator uses a technique called time multiplexing, in which the individual digits are illuminated one after another so rapidly that they appear to be continuously illuminated.
This reduces the number of connections and electronic components required.
The second part of the article provides detailed instructions for building the calculator from a kit.
It explains how to assemble the case, circuit boards, keyboard, power supply, display, and other components.
Special care is required when handling the MOS calculator chip because static electricity can easily damage it.
The LED display also requires precise soldering because many connections must fit into a very small area.
Overall, the WIRELESS WORLD Desk Calculator demonstrates how advances in integrated circuits and semiconductor technology made electronic calculators smaller, more powerful, easier to construct, and increasingly affordable.
The article combines an explanation of this technological development with practical instructions for constructing and operating an actual electronic calculator.
Internet: Link-1