Ok I definitely need help on this. My Cobra alarm has a red led on the dash and I was hoping to change it to a blue led to match my interior lighting. Now looking through the spec the red led is running on 12v and the blue led I have found runs on 3.6v thus I need to put a resistor to get this to work.

 

Now the thing is any ideas what strength resistor do I put and where do I get one ? Also, will this resistor be attached to the red wire of the blue led going back to the control unit or the black one or do I need 2 resistors on both the wires ?

 

Never was an electronics guru so need help guys and gals.

 

 

Cheers !

Ok I definitely need help on this. My Cobra alarm has a red led on the dash and I was hoping to change it to a blue led to match my interior lighting. Now looking through the spec the red led is running on 12v and the blue led I have found runs on 3.6v thus I need to put a resistor to get this to work.

 

Now the thing is any ideas what strength resistor do I put and where do I get one ? Also, will this resistor be attached to the red wire of the blue led going back to the control unit or the black one or do I need 2 resistors on both the wires ?

 

Never was an electronics guru so need help guys and gals.

 

 

Cheers !

aint got a clue on that one,but you,ve just burst my bubble because i thought you WERE a gizmo head with all that talk of remote controll bonnets you posted that you fitted to your zed

http://www.300zx.co.uk/forums/showthread.php?t=67091

Mate, installing a kit according to instructions given and tweaking it to your needs is one thing. Pissing about with electrics with no wiring diagrams and doing things by trial and error with a possble risk of damage is something else (common sense I thought). Didn't realise you had a bubble to burst. Sorry to short fall your expectations.

Mate, installing a kit according to instructions given and tweaking it to your needs is one thing. Pissing about with electrics with no wiring diagrams and doing things by trial and error with a possble risk of damage is something else (common sense I thought). Didn't realise you had a bubble to burst. Sorry to short fall your expectations.

know what you mean about instructions all fvcked up :( by the way i was,nt being funny dude just thought you knew about all that resister shite ;)

know what you mean about instructions all fvcked up :( by the way i was,nt being funny dude just thought you knew about all that resister shite ;)

 

remote control bonnets and HUSD's gotta be a systems diagram freak lol

Que ?

i thought you were the man at this stuff buddy

There is a specific formula to calculate resistant / currents /voltages when you are trying to piss around in my case here. What this formula is I don't have a fuking clue.

 

Secondly, the wires going back to the control unit doesnot show up on the wiring diagram.

 

If I knew the answer bud I wouldn't be posting. However it seems to me I am being mocked for some reason ?

 

Why is this the case with all due respect ?

There is a specific formula to calculate resistant / currents /voltages when you are trying to piss around in my case here. What this formula is I don't have a fuking clue.

 

Secondly, the wires going back to the control unit doesnot show up on the wiring diagram.

 

If I knew the answer bud I wouldn't be posting. However it seems to me I am being mocked for some reason ?

 

Why is this the case with all due respect ?

hey syed ime not mocking no one just seems strange that somebody with your gizmo knowledge should ask a basic simple resister question thats all.iff i could help you i would and in my case its case closed ;)

No worries bud.

I suspect the LED is a bog standard one and there is a probably a resistor somewhere.

Why do you say it runs on 12v? Have you metered it?

I suspect the LED is a bog standard one and there is a probably a resistor somewhere.

Why do you say it runs on 12v? Have you metered it?

i thought the led was a resistor in its own right

I suspect the LED is a bog standard one and there is a probably a resistor somewhere.

Why do you say it runs on 12v? Have you metered it?

 

 

yup, agree with mr S, will be the same just swap like for like

you will need one resistor on the red wire.

 

>> Supply is 12v

>> if the blue LED drops 3.6v you need a resistor to drop the other 8.4v

>> LED's require a current of about 0.02A

>> a 0.02A (20mA) current in the LED will be the same current in the resistor

>> Voltage = Current x Resistance

>> Resistance = Voltage / Current

>> Resistance of resistor needed = 8.4/0.02 = 420 ohms

>> Go for a little higher and make your LED last longer

>> SO : about 450 ohms.

 

 

 

>> if needed: Power = Current x Voltage

>> Wattage of resistor needed = 0.168 watts

 

........

 

However im gonna stop there cos the red led wouldn't be there without a resistor already so im 99% sure you can just swap them over, just put it in the right way round, the legs on the LED should be a different length indicating +'ve and -'ve.

Thanks Guys !

 

What would I do without you all !

10k i think should do it

 

Paul