What is a relay? and what does it do?

[justice 10+ year member]

I have seen relays mentioned a few times in here but I dont know what they are or what they do. Could some one fill me in?

Click to read more...

 

[GPoodle 10+ year member]

Try a search...maybe?

 

[maylar 10+ year member]

A relay is a switch that's controlled by electricity. It consists of a set of mechanical contacts that come together when the relay's "coil" is energized. The coil creates an elecromagnet that pulls the switch contacts together.

Some relays are used to allow a small current to control a larger one. Like if you want to turn neons on with your head unit's remote. You can't wire them directly, because the HU's remote circuit would burn out. So you use the HU to drive a relay's coil, and the relay contacts become your switch for the neons.

Relays are also used for isolation, because there's no electrical connection between the coil and contacts. You could switch 110vac circuits with a 12vdc signal, for example.

Relays can also have multiple sets of contacts that all switch at the same time. Then you can switch a whole bunch of isolated circuits with only one control signal.

Then there's Solid State Relays... but I digress...

 

[Matador 10+ year member]

but is it ok to use the remote wire from the hu hooked up to a relay to run some neon lights? and also to turn on/off the amp? no problems in the long run?

 

[n2audio 5,000+ posts]

Originally posted by Matador but is it ok to use the remote wire from the hu hooked up to a relay to run some neon lights? and also to turn on/off the amp? no problems in the long run?

No problem, but obviously (I hope) your neons would be on whenever your stereo is on. It might be more practical to find a switched source at your fuse box to tap into to turn on your neons (the one labeled "stereo" is usually works well for power that's on whenever the ignition is on).