Electronic Calculator

Philips released some application reports about the EDC100 MOS SET for desk calculators.
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I built one and it still works fine
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Inside view.
Note the display tube, a Philips Pandicon type ZM1200,
a tube with 14 numeric display sections and one 17-pin socket in each end.
The chips are FDY110, FDY150, FDY300, FDY310, FDY320 and FDY360.
The power supply delivers -26 V and -14 V for the MOS-chips (!) and +175 V for the display tube.