Relay computers - OR functionality

From: Tom Jennings <>
Date: Mon Sep 27 16:55:21 2004

On Mon, 2004-09-27 at 14:00, Dwight K. Elvey wrote:

> You don't need the steering diodes if the lines that provide the
> terms don't cross talk to other coils. This is pure relay logic
> and works with AC relays as well as DC. The diodes are only
> needed when you share complex terms that use the same stack of
> contact terms but would otherwise cross talk. The diodes allow
> one to optimize the number of contacts used by sharing common
> terms.

You're right, and while diodes would allow you to conjure up arbitrarily
complex terms of even relay logic, it's also true that solid state
diodes didn't exist back when relay calculators were The Latest Thing,
if these questions are leading to 'why didn't they...'

Though there's always selenium rectifiers, ugh. Besides being toxic,
huge, hot, they are slow and terrible forward/reverse ratio, though
likely faster than a relay. They've been around for a long time, I
wonder how good they' be as a relay signal diode (shudder).
Received on Mon Sep 27 2004 - 16:55:21 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:37:32 BST