Weerstand voor leds
 

Glory,

Heb al veel mensen gehoord die niet weten welke weerstand bij welke led hoort.

de formule is echter simpel :

dus: Weerstand = ( inputvoltage - doorlaatvoltage van de led) / stroomsterkte

inputvoltage; waarschijnlijk 12v of 5v
doorlaatvoltage van de led; hangt af van het soort ledje. Rode leds hebben laten minder door, blauwe laten meer door... neem 2,5 als universeel getal als je het niet weet.
Stroomsterkte; meeste leds verdragen 0,02 Ampère max.
sommige high bright leds tot 0,05 Ampère..
ook hier kun je 0,02 ampère als universeel getal nemen.

U kan dan berekenen bijvoorbeeld:

Een standard ledje op 12 volt aansluiten :

De dichtstbij gelegen waarde is 470 Ohm


hope this clears things up :wtf:


Greetz Anthro

any chance in a translated version for our non-dutch speaking folk?

great post :super:
quality over quantity!

oke morgen komt er een vertalingske, nu slapen... Morgen exaam Frans :puke:

seen there are still so many people not knowing which resistance should be used for which LED ...

the formula is rather simple actually:

meaning:

• Mains Voltage = most likely +5V or +12V
• LED Voltage = depends on the led itself. Red LED's pass on less, blue LED's pass on more voltage ... if you're not quite sure, take 2,5 as a universal value
• LED Ampère = most LED's can only take 0,02A max !
  (exception: some high bright LED's can take up to 0,05A)
  here 0,02A might be used as universal value

so - example given:

the closest value is 470 Ohm in this case ...

Hope this clears things up :wtf:

---------------------------------------------------------------------------------------

all credits go to Anthroplast :ws:

(fair enough ? had nothing to do for about 3 minutes ...)

nice work :king:

can you give wich values resistors have?
between 50 and 1000 ohm or something...

hèhè, those colored strips on the resistor indicate it's resistance...

google tells me this: http://webhome.idirect.com/~jadams/e...stor_codes.htm

and: handy calculator: http://webhome.idirect.com/~jadams/e...esist_calc.htm

MEEEP error

Ter·Angreal posted in the translation:

and this should be as in Anthroplast's dutch post
at least someone is awake @ 23h40
;)

point taken & formula corrected

tnx [Bonbon] :)

you try and translate that text after spending a couple of hours learning physics and chemistry ... eat me :p

I know, duron

my blue leds need 435 ohm resistors
nearest value: 470

=>NEED THOSE VALUES!

commonly it are these standard values, multiplied with factor 1,10,100 ...

• 1
• 1,2
• 1,5
• 1,8
• 2,2
• 2,7
• 3,3
• 3,9
• 4,7
• 5,6
• 6,8
• 8,2

You can get more specific values, but they are more expensive (cfr . metal film resistors).

No you don't

It's always better to have a bit more resistance thus having a little bit less light output (not noticable imo)... always driving @ full speed is also not healty :super:

Could you add another option to the poll?
Because, you explained it well, but I already knew it so it wasn't interesting.

So, don't take that "No, this sux" vote as something negative :).

now stop whining, you li'l twit :grum:
j/k ;)

see Anthro's list below:

1.5+1.5+1.5= 4.5 (x100) Ohm

Is it possible to change the No this sux vote to It doesn't suck, ...
Thx :)

... cuz you've got such a pretty smile :o

Determinating Resistor Values
 

As an addition to Anthroplast's tutorial on how to calculate the resisitor value for led's, I'll explain here how to determinate what value a given resistor has.

First you take the resistor and look for the colorband closest to the side of the resistor (closest to the wire that comes out of it).

Now start writing down the color codes, starting with the first one (duh :)).

After that just do this:
let's say we have written down the following red-orange-green-gold.
Then our resistor value would be:
Red: 2
Orange: 3
Green:100K
Gold: 5%

The value then is: 23 * 100K = 2300K resistor with a tolerance of 5%.
This means the actual value can be anything within a range of 5% of 2300K.

There are also resistors with 5 colorbands. When you encounter one of these just place the digit of the first 3 bands after each other and then multiply with the 4th one, instead of with the 3rd one.
Example: red-orange-green-blue-gold
This would be:
Red: 2
Orange: 3
Green:5
Blue: 1M
Gold: 5%

So we get: 235 * 1M = 235M resistor with a tolerance of 5%.

I hope you all understand, if not, let me know and I'll make some pictures.

To make everything even more easy I made a program in VB last night, feel free to download.
It's in Dutch, but English users shouldn't have to much problems to understand it though.

Download.

OR: you don't download anything and use an html page to determine the resistance

http://webhome.idirect.com/~jadams/e...esist_calc.htm

Or you can download it and use it offline when your evil father forbids you to connect to the internet ;).