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Stats...



1974
1977

size

 227mm
133mm
62mm

1kg



325 rubles

Please see the explanatory note about the price, in the text.



AC 220V, 50Hz, 25W
S/N307
> Mar 1975
046017
Oct 1975
Fluorescent, 8 digits



Factories...

factory mark

Elektronika C3-07

C3-07

Keys  Backplate

When it fires up, I see that leading zeroes are not supressed, and the answer is displayed at the left (zeroes extend right). Displays 0 in a small form. (ie: o instead of 0)

To do 54 * 9 you type  [5]   [4]   [x÷]   [9]   [+=] 
To do 54 ÷ 9 you type  [5]   [4]   [x÷]   [9]   [-=] 


 [+=]   [-=]  The final keypress determines the operation.

"This is interesting, haven't heard of it before. I am guessing though that it wasn't to save keys, but was a result of the way the logic was designed in the ICs. Doing operations with -= and += came about because it took less logic (less transistors) than separate -,+,=. That is probably also the case with the *÷ key, instead of separate * and ÷. Saving transistor space on the wafer dies, not saving keys. Interesting, very interesting.

Your C3-07 looks like an earlier version of my b3-05 I have at home. The keys are the same shape and layout (except mine has an extra row for memory functions) and the digits in the individual tubes is the same (except mine has more digits)." - Kenton Green

8 segment display


Elektronika C3-07

Version 2

© Sergei Frolov
C3-07 early variant
Early variant with Elektronika 4-71b style keys
I have a second version of this calculator - much simpler in keyboard design, but with an amazing 8 segment fluorescent display! The calculator does not work, but fortunately the display lights up. To get the image I had to dismantle the calculator and place it face-down on my scanner, whilst still switched on and connected to 240V! It is interesting to note the extremely low (and hand scratched - not engraved) serial number of 307, implying that this particular unit was extremely early in the production run.

© Sergei Frolov
24-71 digits
The display of the 24-71, manufactured at the same factory.

© Atsushi Ueda
Sharp
Sharp COMPET CS-18D

© Alex Knight
Burroughs C3260
Burroughs C3260
"The amazing display of the C3-07 looks like the early Japanese displays (with their funny zeroes), for example in the Sharp EL-8." - Thomas Brockmeier
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