Calculators

CASIO fx-CG50

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Pictures

Casio fx-CG50 Front view Casio fx-CG50 Rear view (battery cover removed) Casio fx-CG50 Front view (top half) Casio fx-CG50 Front view (bottom half)

CASIO fx-120 (1977-78)

TBD

Specifications

Size 8.4cm x 16.2cm x 2.4cm
Weight (w/ battery) 209g
Type Scientific
CPU Hitachi HD38111A
Registers 2 standard
1 constant
4 bracket
1 memory
Features %, +/-, RV, F, Sci, abc, Sqr, x2, pi, 1x, trig,
hyp, DMS-DD, log, yx, SD, nCr, P-R, n!
Display 12-digit VFD (NEC LD8197A)

Pictures

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Casio fx-120 Front view Casio fx-120 Front view (top half) Casio fx-120 Front view (bottom half) Casio fx-120 Rear view (battery and expansion covers removed

CASIO fx-82 (1982-85)

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Pictures

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Casio fx-82 Front view Casio fx-82 Rear view (battery cover removed) Casio fx-82 Front view (top half) Casio fx-82 Front view (bottom half)

Texas Instruments TI-30 (1976-90)

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Pictures

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Texas Instruments TI-30 Front view (with manual) Texas Instruments TI-30 Rear view (battery cover removed) Texas Instruments TI-30 Front view (top half) Texas Instruments TI-30 Front view (bottom half)

Texet 880 Executive (1977-78)

The calculator measures 74.2mm x 135mm x 22.2mm. It weighs 86g without the battery installed, which is a 9v PP3-type battery. Rather than the usual press-stud type holder, the housing has two metal slide clips. There is also what I assume to be a sponge at one end which is supposed to aid in holding the battery in, however it appears to have gone completely hard and I will most likely replace it in the future. There's small adaptor hole at the top, of which the input isn't specified (though it's generally agreed that it's 4.5v centre-positive).

The case is black & silvery colored with a thin brushed metallic front panel. The eight-digit bubble display has an absolutely terrible viewing angle, which means you either have to be holding it under your coat or against your face to read it!

The keypad is particularly strange in the way that it has 3 cancel buttons,
[CE]
,
[C]
and
[CA]
, while the
[CS]
button is a Clear Sign button, not another cancel! The keys themselves are particularly stiff, and you really have to push them to get them to register. Many 880s suffered something referred to as the "pseudo fixed decimal bug" where, if you typed in
1 + 1.00 = 
, it would display
2.00
instead of the expected
2

Specifications

Size 7.4cm x 13.5cm x 2.2cm
Weight (w/o battery) 86
Type Arithmetic
Logic Algebraic
Power Source PP3 9v
Display 8-digit LED

Pictures

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Texet 880 Executive Front view Texet 880 Executive Rear view (battery cover removed) Texet 880 Executive Front view (top half) Texet 880 Executive Front view (bottom half)