Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!ames!cit-vax!woolstar
From: woolstar@cit-vax.UUCP
Newsgroups: sci.electronics
Subject: Re: Question about multi-switched lights
Message-ID: <2129@cit-vax.Caltech.Edu>
Date: Thu, 26-Mar-87 05:00:33 EST
Article-I.D.: cit-vax.2129
Posted: Thu Mar 26 05:00:33 1987
Date-Received: Sat, 28-Mar-87 00:46:10 EST
References: <18008@ucbvax.BERKELEY.EDU>
Organization: California Institute of Technology
Lines: 30

in article <18008@ucbvax.BERKELEY.EDU>, albert@ucbarpa.Berkeley.EDU (Anthony Albert) says:
> 
> Well, I thought about it some more and figured it out. It requires 2 DPDT
> switches.
> In general, a
>                                                n-1
> circuit with n switches requires each to have 2    poles.
 
A simpler method that I remember from my dad's electrician's handbook is:

        ____      ____      __   __      _____
       /    \    /    \    /       \    /     \
      o      o  o o    o  o o       o  o o     o
              \  /      \  /         \  /
(+) --o        \/        \/   etc..   \/       o--- [light] -----(-)
               /\        /\           /\       
              /  \      /  \         /  \
      o      o  o o    o  o o       o  o o     o
       \____/    \____/    \__   __/    \_____/

    SPDT      DPDT      DPDT         DPDT     SPDT

So it's just a matter of fliping any switch to close or disconnect
the path.  This should work for phones also.

-- 
--------------
 John D Woolverton                      "Yes it's true..."
jdw@tybalt.caltech.edu
 woolstar@csvax.caltech.edu