indicators - led's

[JMallows]

Find out the current that the circuit will use, then use Ohms law to give the value of th resistor: R=V/I Where R=resistance, V=Potential Difference, and I=Current. Hope this is helpful!

Eh?

Sorry, which bit don't you understand?

[VeeDubGTI16v]

its cool i understand.

do i just use one resistor run in series with the 4 led's

[Mixologist]

buy the indicators and cut them up, but yeah they will ahve a resistor or else they will blow up, ask nick he is doing it at uni

Ahem, i doing mechanical, bollox to electrics!!!

[JMallows]

its cool i understand.

do i just use one resistor run in series with the 4 led's

Cool, sometimes i'm not very good at explaining things!

What do i mean SOMEtimes, Never!


You'll probably need two resitors, one for the left, one for the right. Is that what you meant?     You want to aim for about 6-7V, no more though. And its V important to have them the correct way round, ie +ve with anode, not cathode, as LEDs can't be reverse biased.

[JMallows]

buy the indicators and cut them up, but yeah they will ahve a resistor or else they will blow up, ask nick he is doing it at uni

Ahem, i doing mechanical, bollox to electrics!!!

Whats wrong with electronics??    

[VeeDubGTI16v]

its confusing

[Mixologist]

yeah, you can't see whats going on!!!

[JMallows]

This is true i suppose!!!

Had a (hopefully helpful) thought for you. Wire up the diodes, and then use a tansformer and a potentiometer to find out the best operating potential. Enough to be at their brightest, but not too much they start to go funny colours!!    I reckon it'll be about 7V, maybe less, probably between 6 and 7. Then us this in the formula. It should all work, let me know if if it doesn't, and if it does, wanna see how good it is!

[VeeDubGTI16v]

ok cheers for help jmallows. im not gonna do it just yet, ive got loads of stuff to do first before i relocate the indicators (like finish the bumpers :-[ )


cheers

[jazzygm]

if you are buying the LED's off of somewhere that specialises in selling them, or an electronics company like maplin (www.maplin.co.uk   ) then they will have things such as forward current and forward voltage noted.  Then from R= V/I

Supply Voltage(V) - LED Forward voltage(V)
LED Forward current(A)

Where the supply voltage is errrr... 12 Volts... it being a car!

Always go for a slightly larger (not overly larger!) resistor than needed to protect them a bit, and you need the highest candela rating you can get.

anything else? oh, ive heard that if you gently file the tip of an LED the light will diffuse a bit better. dont try it unless you've got a spare though! and the potentiometer is a good idea... as long as you are very careful, IIRC theres a very fine line between maximum brightness and burning it out! And they need to be the right way round... hence forward voltage  

HTH!