Simple Relay ALU

A project log for RISC Relay CPU

Scientific calculator with a brain built out of relays.

roelhroelh 11/08/2018 at 14:333 Comments

Since you are all Relay Computer builders or fans, you might be interested in the new extremely simple Relay ALU, that provides 10 functions with only 2 DPDT (or 3 SPDT) relays and a few diodes ! 


Yann Guidon / YGDES wrote 11/09/2018 at 03:24 point

Thanks for thinking about us SPDT peasans :-D

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roelh wrote 11/09/2018 at 08:58 point

Yes, I thought about your project when I mentioned the SPDT count in my new Relay ALU project...  But I am already thinking of a use for the 4th relay contact of my two DPDT relays....  So your joy might not last long...

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Yann Guidon / YGDES wrote 11/09/2018 at 09:33 point

In fact, to be honest...

It's a nice thing because relay coils can be connected in series to get more contacts.

Your design uses a SPDT and a DPDT, which would require 1 and 2 SPDT ... and a different control voltage for each.

By going full DPDT, your redesign will be doable with two couples of SPDT, so the control voltage is the same. Neat !

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