Sharp EL-8

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Sharp EL-8
Sharp EL-8.jpg
Other namesFacit 1111, ADDO-X 9364
ManufacturerSharp
Introduced1970
Calculator
Display typeVFD
Display size8 digits
Programming
Other
Serial Numbers1012099

The Sharp EL-8 was an early handheld calculator produced by Sharp starting around December 1970.

Special features[edit | edit source]

Since the calculator uses the Itron font tubes it does not feature leading-zero supression, to help with readability (e.g. it would display '00000001' to display '1').

The calculator uses separate 'minus equals' and 'plus equals' keys, as well as a single key for multiplication and division, this was common for the time period.

Internal design[edit | edit source]

The calculator uses 3 PCBs internally, one for the logic, one for the display, and another for the power supply, the logic board and display board slot into a card-edge connector mounted to the keypad assembly, with the power board being connected to the display board via a wired connector and mounted with screws.

The calculator uses a reed-switch keypad, Vacuum Fluorescent Displays (8x Itron DG10L and 1x Itron SP8A), and 9 Integrated Circuits, the Rockwell AC2261, AU2271B, DC1152A, NRD2256, the Hitachi HD3121, and the NEC μPD190C.

Sharp EL-8[edit | edit source]

The Sharp EL-8 came in the colors black and white.

Gallery[edit | edit source]

  • Powered on.

  • Bottom case.

  • Badge (#1012099).

  • Rear of internals (with battery-bypass capacitor mod).

  • Sharp EL-8 internals (Rear 2).jpg

  • Front of the internals.

  • Sharp EL-8 internals (Powered on).jpg

  • Powered-on without the display cage, there is copper tape against the back of the tubes and without the tape having a connection to ground the tubes will light dimly and unevenly.

  • Top of the keypad cage.

  • Bottom of the keypad cage.

  • Display board assembly.

  • Top of the logic board.

  • Bottom of the logic board.

  • Top of the power supply board.

  • Bottom of the power supply board (with battery-bypass capacitor mod).

Carrying case[edit | edit source]

The Sharp EL-8 came with a carrying case, the zipper latches shut and the carrying handle can button into 2 positions, with the handle extended or retracted.

  • Front

  • Side, showing buttons

Sharp EL-81 Power brick[edit | edit source]

The Sharp EL-8 came with a Sharp EL-81 power brick for charging and powering the calculator.

  • Top of the power brick

  • Bottom of the power brick

EL-84 Battery[edit | edit source]

The Sharp EL-8's battery pack is a 7.2v rechargable nickel-cadmium (NiCad) pack made up of 6 AA-sized cells.

  • Sharp EL-84 Battery pack

Facit 1111[edit | edit source]

  • The front of a Facit 1111

ADDO-X 9364[edit | edit source]

Battery-bypass capacitor mod[edit | edit source]

To bypass the requirement of the battery pack you can put a capacitor across the battery terminals, a 470uf 16v cap is approximately what you want.

  • Battery-bypass capacitor in a Facit 1111

This mod uses D-SUB pins ("nixie pins") soldered to the capacitor, and the capacitor hot-glued in-place of the battery, to make the mod reversible.

External Resources[edit | edit source]

See also[edit | edit source]

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