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How do I use a relay? Answered

I have never used a relay before, and I don't know a lot about them. I think I might need one but i'm not sure exactly how it works. From what i understand, when electricity is passed through one set of pins, another set of puns allows a charge to be passed through, like an electricity powered switch. I might be completely wrong, and if anyone could help that would be great.

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user
lemonie (author)2012-07-10

I think I might need one

For what / why?

L

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tim127 (author)lemonie2012-07-11

Me and my friend are working on a project and were thinking of different ways to do the circuitry and a relay seems to be the easiest.

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lemonie (author)tim1272012-07-11

What do you intend to switch?
Solid-state semiconductors might be better.

L

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tim127 (author)lemonie2012-07-19

I am planning to have an Arduino power the relay to turn on a 120v motor.

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AndyGadget (author)2012-07-11

 
You're right - A relay is an electrically operated switch.  It can be operated from a manual switch, another relay or electronic circuitry.

I started typing a reply but it was getting rather long and involved so I think the best thing is to refer you HERE where there's a pretty good description of how relays work.  ('commom' is a typo of 'common).

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iceng (author)2012-07-10

It is important to understand the current carry capacity is is much greater then the switching current of the relay or any mech switch contacts...

A

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tim127 (author)iceng2012-07-11
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Re-design (author)2012-07-10

You are right. the pins that power the relay connect to the coil. The switch contacts have a rating as to the max. power they can switch. If you go over the rating you will burn out the contacts.

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