DIYbanter - View Single Post - Advice please - 3 way light switches

mm wrote:
On Mon, 16 Jan 2006 12:02:15 GMT, (Beachcomber)
wrote:

Three way (and four way) switches are mis-named but no-one ever
bothered to change the term for a better understanding of common
electrical use. A three way switch is more correctly termed a Single
Pole Double Throw switch (SPDT). Why then, is it called a three
way switch? Because it has three terminal screws on it?! Very
strange.

LOL. Good point.

'm sure whoever called it "3-way" first knew exactly how it worked. I
wonder what he was thinking.

It's 3-way because there are 3 different ways the light can be on.

S #1 "up" S #2 "Up"
S #1 "up" S #2 "down"
S #1 "down" S #2 "up"

or Switch #2 "