Re:The smart home is flailing as a concept
by mauvehaus on Friday August 06, 2021 @01:13PM
(#28090116)
Or in other words if you're used to seeing switches from the electronics side of the world:
2 way: SPST
3 way: SPDT
4 way: DPDT
I once lived in a house with a 5(!) gang box with three of the switches wired to the upstairs hall light incorrectly and another switch upstairs. It was as big a mess as you'd imagine.
A 2-way switch has two terminals and gives a closed (on) or open circuit.
A 3-way switch has three terminals and gives you one terminal tied to either, but not both of the other two.
A 4-way switch has four termimals and gives you two terminals which are each tied to the other two terminals and you can pick; these also give you a big headache when one switch of many fails and one circuit path is open, but many paths still work.