Calling all electonics nuts

[Devils]

Hey guys,

I need to simulate a standard H4 globe (hi/lo) using a relay or two.

So with a H4 globe there is 1 common pin and 2 other pins, one for each filament.

If i was to use a 87a (5pin *change-over*) relay... would i be correct to wire it like this.

Pin 30 = common pin on the globe.
Pin 87 and 87a would be the seperate hi/lo pins (need to find out which is dominant, i.e which would need to go on the resting 87a "low beam').

But now... how would i go about switching it?

Jump pin 30 (which would be a constant positive on the common pin). To pin 85 using a diode blocking towards pin 85.

Then jump pins 87 AND 87a seperately using a diode each blocking to wards pin 86 to which they would both be connected.

Does this sound about right? I'm going to try it anyway but just thought i'd put it out there incase someone could shine some light on it for me.

So the block would be, toward pin 85 with positive going to it. Then a diode between pin 85 & 86 with the block towards pin 85. Then both 87 and 87a joined to pin 86 both with diode blocking towards pin 86.

[Devils]

Actually just realized that if i do that the relay would be constantly switched... so i'd only need a switch from the high beam.

What is the resistance of a filament? Will i need to put a resistor inline in the out going pins (87 and 87a) to simulate a filament?

[Devils]

They have a 1.8ohm resistance across the board...

I.e.

Common to low = 1.8
Common to high = 1.8

Low to high = 1.8.

So maybe i dont even need a relay, maybe just 2 1.8ohm resistors between Low pin and common, then high pin and common?

[wilbo666]

What are you really trying to do? Maybe we can help you more if you tell us that?!

Btw a 1.8ohm resistor is going to get pretty hot


Cheers
Wilbo

[Devils]

As i said in the first post, i'm trying to 'simulate' a standard H4 globe!

When i have globes plugged into both sides, the relay will switch from low to high, when i've only got one globe in one side, the relay will not switch low to high.

So i want to simulate having a globe plugged into the other plug so that the relay will allow switching without actually having a globe in there.

So i figure, seen as the globe filaments are 1.8ohm resistance (which isn't much so they shouldn't get hot, and depends on the wattage resistor i get anyway) by putting a resistor between the pin for the low beam and the common pin, and also a resistor between the high beam pin and the common pin, that should simulate a globe?

That's what i'm asking... and just drove all around town... all auto leccys normal leccys and the two electronics shops are closed until Monday

[wilbo666]

Right....

Why do you need to simulate the globe, why can't you use a globe? Is this in the AW11?

1.8ohms, at 12V that will be 6.66Amps (I=V/R), or 80watts (P=VI)....80watt resistors aren't small

I don't understand why you need the globe in? All the cars I know can switch between low and high beam with the low beam globe out? Is there something special about the wiring in your car??

Cheers
Wilbo

[Devils]

Does it matter?

If you know the answer to the question, the reasoning behind the question doesn't matter!

Because (as per other thread) i've installed a Hi/Lo HID kit which only plugs into ONE side. But on the AW11 BOTH sides NEED to be plugged in to get the hi/lo to work!

Hence the question.

P.S. Dont want to leave a bare globe just dangling there as 1) it will get very hot. 2) it'll look weird as all the area behind/under the headlight pop-up will be lit! haha

EDIT: Damn... i've used 2k 10wat resistors and they weren't that big... 80w i can understand... i was just looking at the 'resistance figure' and thinking it was relatively small. I'm not that great when it comes to resistors etc.

[wilbo666]

Of course it matters

If we know what you are trying to achieve we might be able help in a more constructive manner

Can you do up a little hand drawn schematic? A link to the HID kit wiring diagram?

Cheers
Wilbo

[quiksilv]

You could probably use say 10, 20ohm 10W resistors in parallel?

[Kebin]

http://www.toymods.net/forums/showthread.php?t=27195

[Kebin]

Of course it matters

If we know what you are trying to achieve we might be able help in a more constructive manner

Can you do up a little hand drawn schematic? A link to the HID kit wiring diagram?

Cheers
Wilbo

Typically they are like this:
http://hidkitshop.net/files/Bixenon.pdf

[Devils]

Thanks Kebin, but as i said in that thread you linked to... that PDF just shows how it is 'ment' to be wired... not how it needs to be wired to work in my car!

[bansheebuzz]

take the dash warning light out