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A project log for Germanium Calculus

Retro calculator that uses only antique germanium semiconductors ;)

shaosSHAOS 04/22/2016 at 02:586 Comments

This is basic board (3-input germanium NAND with indication if all inputs are 1s) that will be used here (and there #Clockwork germanium ):

Manufactured by oshpark.com

Another thing was taken from old Soviet phone (and sold to me through eBay ; ):

This one will be used to input decimal digits into calculator ;)


UPDATE (04/22): Soviet nixie tubes have arrived :)

Discussions

Yann Guidon / YGDES wrote 04/22/2016 at 03:05 point

Oh yeah, i'll have to use that kind of dials one day :-D

Do they exist in hexadecimal ? :-P

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SHAOS wrote 04/22/2016 at 03:20 point

never seen anything different from decimal one ;)

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flashcactus wrote 04/22/2016 at 09:03 point

don't think so, this type of dial was invented for pulse-dial telephones specifically, and pulse-dial is a pretty inefficient avriable-length encoding not used anywhere else (but ideal for electromechanical automatic switchboards). anything computer-ish would have used keyboards from the start.

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Yann Guidon / YGDES wrote 04/22/2016 at 09:34 point

It seems I'll have to limit to octal then :-D

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SHAOS wrote 04/22/2016 at 14:02 point

Nope, I remember a number of circuits from my childhood where
pulse-dials were used to enter digits into digital system built from TTL
chips ;)
BTW I plan to use rings of flip-flops to represent decimal
digits, so "pulse-dial" wheel looks like a natural choice from this point of
view :)

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flashcactus wrote 04/22/2016 at 14:05 point

I suspect those were more a consequence of the wide spread of PD telephones than anything.

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