[AT] What is a Relay?

[Spencer Yost]

Relays are just a remote switch that uses a very small electric current
called a control current to "operate" the switch.  Control current present?
- The relay is "on".  Control current off? - The relay is "off".  In fact,
the solenoid  on the starter of your tractor is just one big fat honking
relay.

When it comes to lights, they draw quite a bit of power so adding lights
(whether trailer or auxiliary lights) to a circuit sometimes requires your
wiring be beefier than it currently is or the wiring will catch on fire.
If your wiring isn't beefy enough, a common work-around is to create a
separate circuit wired directly to the battery (with its own in-line fuse)
and then use a relay wired to the original circuit as the "switch".  The
current required to operate the relay is minuscule so there is, for all
intents and purposes, not an additional load on the original lighting
circuit.

BTW, this is a common trick to add field lights to antique tractors so I am
not going to add the "OT" label to the subject line,

Hope this helps,

Spencer Yost
Owner, ATIS
Plow the Net!
http://www.atis.net

*********** REPLY SEPARATOR  ***********

On 12/10/2004 at 9:03 AM Ricky Prescott wrote:

>How does a Relay switch work?  My lights on my truck went out.  It burned
>up the plug that goes into the switch.  I rewired it. My Mechanic said I
>need to install a relay so when I hook up my trailer lights it won't burn
>up the plug again.  I am wondering what I need.  The wiring in the  old
>dodge is not heavy enough to handle all the amps the trailer lights draw. 
>I hope I made this clear.  Thanks, Ricky 
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