2-way and 3-way switching...

["Harrison, Mark (Alliance)" <Mark.Harrison@xxxxxxx>]

Now, please don't laugh, and don't say X-10, but can anyone remind me how
to wire a three-way-switchable light.

I can do a one-way or a two-way so that whichever switch is thrown, then
the light "changes state", and I remember seeing a wonderfully
elegant design that did three-way, but I can't remember how....

A one way is:

/ ----b
/
a---S1
\
\

If S1 is set so that a and b are connected, then the light comes on.
If S1 is set so that a and b are not connected, then the light goes off.


A two way is:

/--------\
/          \
a-- s1      s2 --b
\          /
\--------/

If S1 and S2 are set so that a and b are connected, the light comes on.
- This happens if S1 is set to the upper position AND S2 is set to the
upper position
- This happens if S1 is set to the lower position AND S2 is set to the
lower position
If S1 and S2 are set so that a and b are not connected, then the light goes
off.
- This happens if S1 is set to the upper position AND S2 is set to the
lower position
- This happens if S1 is set to the lower position AND S2 is set to the
upper position




Mark Harrison
European IT Manager, BP/Bovis Alliance
New Tel No: +44 7010710239
Fax: +44 20 8423 7711
SMTP: Mark.Harrison@xxxxxxx
http://connect.bpweb.bp.com/search/record.asp?IDN=137987
http://bp-bovis-alliance.extranet.bp.com

------------------------------------------------------------------------
Telebank Money Market yields are consistently DOUBLE the national average
and CD yields in the TOP 1% nationally for 10 years! FDIC insured.
Click for FREE Information Kit. http://clickhere.egroups.com/click/1124


eGroups.com home: http://www.egroups.com/group/ukha_d
http://www.egroups.com - Simplifying
group communications