Hi Guys & Girls!

I need to put a 12v illuminated switch into a simple circuit but the switch has 4 terminals which is confusing me!

I have a 4.2 amp 12v supply (+ & -) and want to run 3 computer fans which will draw less than 1 amp

I purchased one of these switches to do the job http://www.maplin.co.uk/Module.aspx?ModuleNo=34859

Two of the terminals are marked only i.e. one marked Plus the other negitive, but the other two terminals aren't marked and so i can't figure out how to wire it up

If it had been a three terminal switch then i believe one would be power in, one would be power out and the third would be ground

Can any of you help please. Thanks Andy

 

First make sure the light int he switch is rated fro 12v and not 120.
From your description it sounds like it is, the +and - being used for a led. The other two terminals are your switch. You would tie the - to the negative or ground, the + would go to the wire that is being switched and the two other terminals would be your + in and your switched out.

 

Hi Gerty,

That makes sense now! I will give it a go.

Thanks for the fast reply

Andy

 

The FAQ indicated that a 430 ohm resistor is needed for 12 volt operation so the LED does not burn out.

 

Good catch beenthere, I forgot all about the resistor!!