Name/kind of switch

[jobin]

I want to install a switch which can feed either of two circuits but always at least one of them, never OFF. Does this kind of switch have a special name, and are they common?

 

[RedHerring2]

Change-over switch?
I've used similar, e.g. sending sound to different speakers, depending on where I am in the house, also using one set of keyboard/mouse/monitor for more than one PC.

 

[Paul_C]

2-way switch (a.k.a. 3-way in some parts of the world). And yes, they're extremely common, most often used to control a light from two different locations.

 

[jobin]

Have learned that this is what i want: Single Pole Double Throw Switch.

See here http://www.1728.org/project2.htm
towards the bottom of the page.

 

[Paul_C]

Different terms for the same thing:

Single throw = 1-way
Double throw = 2-way