The Casio Mini showing its 6-digit display, lack of decimal point key, and its uncommon right-arrow key.
Distinctive features: Low-cost hand-held calculator. Does not have a decimal point key.
Display is 6 digits, green fluorescent, individual tubes.
4-function, decimal point fixed at the far right of the display. Another 6 less significant digits are revealed by pressing the right-arrow key, as demonstrated below.
Integrated circuits - Hitachi HD32127P & NEC uPD129C, here date coded 1972.
6v (4x AA).
148 x 75 x 42 mm (6.1" x 3.1" x 1.3").
Introduced August 1972. Price in U.S.A. in November 1972 was US$59.95.
Casio Computer Co., Ltd., Made in Japan.
Inside the Casio Mini, revealing the six miniature fluorescent display tubes.
The power supply board, underneath the main circuit board, which produces the higher voltages for the fluorescent display tubes.
The Casio Mini has no floating point and lacks a decimal point key, so you cannot enter numbers with decimal points. However it can display the digits to the right of the decimal point as shown above.
Here 22 has been divided by 7 to give an approximation to PI. The display shows 3, but by pressing the right-arrow key the digits to the right of the decimal point can be seen, 142857, giving the complete answer 3.142857.
When introduced in August 1972 the Casio Mini had a very low and competitive price, below US$100.00 [£40.00 Sterling]. This was achieved by limiting the display to 6 digits, using fluorescent tubes (then cheaper than LED displays), and manufacturing in very large volumes. It was thought that most Japanese users would use the calculator for currency calculations and would be happy with a calculator that could calculate with whole numbers to ¥999,999.
The quality is much better than that of the similarly priced Rapidman 800.
The Mini was updated several times over the next few years (with added model number on the back) as the CM-601 to CM-605, all with a similar horizontal layout, and lower prices.
These were followed by the similar Personal Mini models (CM-606 & CM-607).
Due to its low cost this calculator family sold extremely well and fuelled the calculator price war in this period.
© Text & photographs copyright Nigel Tout 2000-2015 except where noted otherwise.