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Size
(approx):
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67mm
x 130mm x 31mm (max) (w x h x d)
Weight 82g not including batteries.
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Power:
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9.0v
DC using 1 x PP3 size battery.
It accepts an adapter (9V DC 500mW) through a socket on the left
side just above the display.
The on/off switch is on the right side at the top.
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Case: |
The
case is two-piece black smooth plastic with a raised upper section (which
helps accommodate the battery.
A printed black label sits in its own recess on the top panel.
The red display filter is angled and convex to act as an additional
magnifying lens.
It gives a clean bright image with very limited angle of view.
The subtle coloured keys are short travel, positive click type that
work well, although they rattle like a box of matches when shaken.
They are lozenge shaped with little indents to.
White text is printed around the keys for labels. |
|
Display: |
8
digit red LED with bubble lens and a ninth digit for negative and error
indicators. |
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Features: |
Standard
four functions with percentages, change sign, register exchange and
four-function memory. |
|
Age: |
1978
(receipt for from Currys, Chippenham, UK on1 August 1978 showing a cost of
£4.95.) |
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Manufacturer: |
Unitrex
by Radofin, made in Hong Kong.
Serial number 1322 (very short!) |
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Comments: |
Cheap
and cheerful calculator which feels very light but is nevertheless quite
attractive.
The logic is sound except for the fixed decimal point bug and lack
of square root.
This case design was used for a variety of brands. |
| Logic comments: |
The
(C/ce) key is used to once cancel an entry whilst a second press clears
the whole calculator |
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Input
overflow is suppressed inputting an ninth digit is ignored |
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Negative
numbers are shown with a "-” in the immediate left digit travelling
into the far left (ninth) digit, thereby allowing full eight digit
negative numbers. |
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There
is an automatic constant on all four functions |
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The
change sign function can be used in mid number entry. |
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Divide
by zero shows “C” in the far left (ninth) digit and is recoverable
using (C/ce). |
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Overflow
shows the result and “C” (“E” if negative) in the far left (ninth)
digit and is recoverable using (C/CE) |
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Ex
is used to exchange the display contents with the last register so that
(9)(/)(3)(EX)(=) gives the inverse “0.3333333” |
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Memory
storage is not indicated – you have to remember it |
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The
percentage function just divides the number by 100 |
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This
has a “zero decimals” bug: try
(0)(.)(0)(0)(+)(1)(=) gives “1.00” as an answer. This pseudo fixed decimal point system remains until you
multiply or divide. The
number of points can increase though. |
