i'm pants with electrics, can anyone explain why & how to use a relay, what its use is
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i'm pants with electrics, can anyone explain why & how to use a relay, what its use is, is it a type of switch, my wiring for anything is basic at the best of times but now i'm turning into to doing most stuff on my car i feel knowing what relays are for where n when to use one or more would be enough fior my automotive needs, i think? any help is appreciated chaps

SKYLINES ARE LIKE CLITS, EVERY FLANGE SEEMS TO HAVE ONE: see this sticker on my silvia

the Search-section on this forum is blummin superb & simple to use, unlike some other forums, without the search-section & the help of this bunch of chaps on here i'll never be able to !!!Start the day with a 998cc turbo!!! :) i'm getting closer though!

Tom Fenton says: I have it all, make me an offer

In short they are effectively switches where you use a low signal to switch on a high power application. For example headlights take a hundred watts or so where however you would want this kind of power running through the switches on your steering column as it would more than likely fry the switches, so you use a relay to go between the switches and the lights. Does that make sense?

that sorta makes sence rob, so the feed from a switch for headlamps for instance is low & i have those blue offroaduse only halogen bulbs, the relay stops the big current going the curcuit to the swich, if that makes sence! :

i only have one on my mini before the solinoid for the pre-enguaged starter motor, i'm asking these leccy questions as i've moved my loom iside & when i fit megajolt i want to ensure i dont fry it!

a few failsafes in my wiring are needed, relays & proper fuses, i dont understand wiring too well

SKYLINES ARE LIKE CLITS, EVERY FLANGE SEEMS TO HAVE ONE: see this sticker on my silvia

the Search-section on this forum is blummin superb & simple to use, unlike some other forums, without the search-section & the help of this bunch of chaps on here i'll never be able to !!!Start the day with a 998cc turbo!!! :) i'm getting closer though!

Tom Fenton says: I have it all, make me an offer

Exactly what rob said. You connect the small coil in them which is basicly a switch to whatever switch that you want to control them and then another 12v supply to them and then you can switch really high current eg headlights, cigarette lighter etc and only put very minimal current through your opperating switch. Amazingly simple device.

but you gotta know where ya connecting on the relay, low volts to low volt post then high volt output, am i sorta on the right track???

if anyone has any pics or diagrams that would help, i'd be ok then i think

SKYLINES ARE LIKE CLITS, EVERY FLANGE SEEMS TO HAVE ONE: see this sticker on my silvia

the Search-section on this forum is blummin superb & simple to use, unlike some other forums, without the search-section & the help of this bunch of chaps on here i'll never be able to !!!Start the day with a 998cc turbo!!! :) i'm getting closer though!

Tom Fenton says: I have it all, make me an offer

good clickable picture thing on page 2

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Don't get confused with low voltage and low power. All car stuff that you will deal with is 12v (apart from a 6v coil, but forget about that)

As has already been said, all the relay is used for is to allow smaller lower power switches power high power uses.

Evolotions link is quite informative. On this one it shows a relay circuit. (in a car application there will only be one battery)
http://home.howstuffworks.com/relay1.htm

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

In short a small amount of power is used to magnitise a coil that operates a switch that can deal with a larger amount of power

A solenoid is something that gives mechanical movement for an electrical input but in the starter solenoid that movement is used to operate a big switch, i.e its a relay.

In the case of the pre-engaged starter they have a relay that operates a solenoid, i.e a relay operating a relay! Confusing huh..

This is because the solenoid itself (being a BIGASS relay) draws quite a bit of power, too much for the little ignition switch so a regular relay is needed to operate it.

Terry

Edited by Turbo Tel on 28th Jul, 2008.

website:- http://www.terryhunt.co.uk