GolfGTIforum.co.uk

its cool i understand.

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

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.

its confusing

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!

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!