LED Wizard

[jolly_tas]

Thought I would post this link seeing as how LED's are becoming a more popular modding item.

I found it very useful to help work out the setup for LED lighting and particularly resistors needed.

note: for quick use, the usual forward voltage for 5mm LED's is 3.3v and forward current is 20mA.

http://led.linear1.org/led.wiz

[Graham]

Interesting site, could be very helpful, thanks

[Blakey]

Thought I would post this link seeing as how LED's are becoming a more popular modding item.

I found it very useful to help work out the setup for LED lighting and particularly resistors needed.

note: for quick use, the usual forward voltage for 5mm LED's is 3.3v and forward current is 20mA.

http://led.linear1.org/led.wiz

actually for white LED normal voltage is 3.3 at 20mA for the normal type leds

white 3.3
red is 2.2
orange 2.2
blue 2.8
green 2.4or 2.2

all at 20mA-30mA

for piranna or ufo type same voltages but at 40 - 50mA

and for Luxon same voltages but 350-700mA

[tryg]

who would rely on those voltages? You would be resisting those LEDs prior to adding those to you project, right????

Personally, all my LEDs are chained with resistors to make them stable 12v applicable.

[Blakey]

ok with out those voltages how do you work out your resistor?

to make your LED stable for 12V?
anyway all leds can be used with 12V no matter what there voltages are.

all the voltage of a LED is how much of your source voltage is lost as it goes through that resistor. so if you have a 12V source and a LED of 3.3V then you only have 8.7V left after that LED. so you can only put 3 3.3V LED in series. BUT you can put a large amount of 3 in series LED's in parallel..
as every parallel has the same voltage going thought it. where as every series has a voltage drop across each LED, but it has the same current going thought it. so if your LED array uses 20mA then for every series of 3 LED's you only use 20mA.

and yes you can make every single LED 12V Usable sometimes that is easiest, but if you don't have to then doing so is a waist of power even tho is would be quite small. but still if you have 200 3.3V LED's all signally set up for 12V then you are using 4A that is alot of power for only 200 LED's but where as you have them in a 3series parallel array then those 200 LED's are only using just over 1A that's a pretty big difference.

the resistor that you use on LED doesn't so much as change the voltage. it limits the current. going through the LED. yes can lower the voltage with a resistor but then you would have to have a constant Current.

but that is pointless. cause shy of owning a doble you cant really make something that easily to put out a constant current.

if you really want a estimate of what voltage your LED wile use in your arrays, then get a multimeter shift it to Diode and hook your LED up to it, and it will give you the point of where the voltage first breaks though the diletric. on a white proper voltage of 3.3 a multimeter will show about 2.8-2.9. yes at those voltages it will light up but it will be dull.

[tryg]

wow, thanks for the school lesson... the rest of us buy the resistor with the LED...

Its all been worked out for us...

[jolly_tas]

If thats the way you want to go then here's a good place to get them...

http://www.ledsales.com.au/catalog/inde ... 48_152_154

[Blakey]

but even that those ready made leds are pretty expensive. seeing as you can buy every 1/4W resistor for like 2-3c ish and if you buy from the right places you can get bright LEDs for like 0.099c for blue (most expensive besides IR) so if you make your own instead of costing 50c it cost 2.099c if you are buying alot that is a really good saving. a place iv been talking to ofey about you can buy about 500 Bright LEDs for about $10 depending of what you buy.

[Ellimist]

just to continue the school lesson a car battery at full charge will normally read 14v not 12v.

i'm bored what can i say LOL.

[spunkybob]

just to continue the school lesson a car battery at full charge will normally read 14v not 12v.

i'm bored what can i say LOL.

Actually the battery will only read 14v when the altinator is going otherwise its between 12 and 13

[Ellimist]

no it won't it will read 14 if you pull it straight off the shelf charged.

[tryg]

Might do, but most batteries read lower once in the car for a while... I get 14.4 off the alternator.

The resistor in these LEDs are rated to work from 6v-14v anyways...

Yeah, Blakey can get them all for dust, but these come pre-wired from factory and they look neat. I am sure you can use your 50c saved for the next mod.. the rest of us who could care less about that sort of money, compared to the time saved will be working on the next mod already...

Just my 2c

[Ellimist]

ah it will make bugger all difference the voltage tryg. i had a long discussion with the century rep when he was in at work one day about why the read 14 and not 12 like most people say.

really its just something rando that doesn't matter at all anyway.

[tryg]

you're right it matters not.... because the LEDs work at 14, 12, 10, 8 and 6v

[Blakey]

just to continue the school lesson a car battery at full charge will normally read 14v not 12v.

i'm bored what can i say LOL.

that is tru but its the alternator that reads 14V a normal car battery not on the alternator, is like 12.2-12.6 i believe, if you rate your resistors for 12v, amperage the increase of those 2 volts wont be alot more miliamps and most LED have a 10 or 100mA greater as there max,

the normal LED 20mA- is the min/normal they usually have a max of about 30mA before they burn out and become the elusive black LED