Pyrophilus

Hello again,

I have a question on relays. I don't know much about them except that they are "switches" that are activated by current...

I just have one question. The Hella relay that I used for the foglamps was one where the relay by default is "open" when there is no current. When the fog lamp switch is turned on, it sends current to the relay, causing it to "close" the circuit, turning on the foglights.

I was wondering if there were relays that did the opposite. Meaning, when there is no current applied to the relay, it by default keeps the circuit closed (and the object powered), and when current is applied to the relay, it "cuts" the circuit...

Thank you for all the helps,

Wiking

Relays are used to:
- isolate different voltage level circuits
- isolate driver logic/switch from device generated spikes
- small current [read: thin wire, skinny switch] can be used to drive big currents
- remote device wire ctrl

Install one relay between ign switch and starter solenoid. Quadruples ign sw contact lifetime as arching during contact is minimal compared to solenoid.

There are many kinds of relays available, like u said. Relay pairs, relays with timing going on or off, blinkersblankers with electronics in...etcetc
One mystery problem u might once get on installation, is with two adjacent relays: the other can keep the adjacent energized if no diode is attached to drain that non energized relays external field to gnd.

internetautomar

iTrader: (30)

simple answer yes.
much longer answer with more info than I care to type http://www.the12volt.com/relays/relays.asp

Pyrophilus

Hey, I don't wanna get all mushy, but I just want to thank everyone here for all the very useful help. Like I read somewhere, I am so glad that I have a 3rd gen because I have learned (am learning) so much about cars and electronics. I hope the new year has in store many nice things for all the helpful folks on this forum.

Internetautomar, I actually did read this a long time ago, but I guess I wasn't paying attention. Plus, the Hella relay that came with the driving light didn't have 87a! Anyway, thank you again for the help.

I was looking for these kind of relayes because I wanted to install a back-up sensor for our '01 Pathfinder (someone around here just ran over their child in the driveway). I know that we are careful, but I don't think people run over their kids on purpose, plus, my boss knows of 2 people that have done that (1 death) in 12 years and that's 2 two many...

Anyway, I got an aftermarket, but we have a 10month old, so I wanted the ability to "turn off" the annoying beeping noise. But that defeats the point of having the sensor if we accidentally leave it off, so I thought maybe get a red illuminated when on switch and toggle to the above said relay, so that when we disable the backup, the switch will glow red reminding her that it is off...

I know some maybe think it's cheesy, and even two years ago, my wife and I would have gone off at the stupidity of the parent that ran over the kid, but after seeing footage of the tsunami washing little children away from parents' arms and then hearing about this freak driveway accident, I just am bit paranoid...

Thank again for all the help...

Wiking

Btw: Where is our forum swede phasta? Scandinavian Flags are in half staff...

The only sure thing for us is that the day of givin'up all is today one day nearer, approaching. Thereby the only thing that matters, is the destination you/me select today.

Planning and being secure is wisdom. Spending all time on that (not saying u do) is hell on earth. And what for? If the one soul dear to me is to be called home today, there's nothing u can do about it... this year, '50' million people dies, '100' million will be born. Can u comprehend this soul mill rotating? Only thing that makes sense is what happens to me after this mill... Having said that, I'll move only after I see the kids, they're so wild that half a second makes difference... oh whata menace...

So having good safety measures is good, how its done has to be practical as u just explained. Mirrors placed critically are good. And be happy.

"Installing a microswitch and warning light to indicate if rear bumper drops off, is NOT wisdom"