LED setup questions

[Talisen]

Hey,

I'm working on a PKD that I want to put 5 Blue (waterclear) LED's into.

I have four 3mm (5v 20mA) and one 5mm (5v 20mA?) And a 6V battery.

I've tried a few things and I can say that with two of the 3mm LEDs hooked up to the battery, the light output is great (so is that just 3v through each?)

Can someone tell me what the correct method/path/resistors/etc to use?

I did try a few websites, but I'm not an electronics guy so it really was greek.

 

[exoray]

Get yourself some 56ohm resistors probably easier to find 68ohm and they will work just fine...

+ led resistor - Each LED should have it's own resistor and be wired in parallel like the picture below... The picture is just for wiring reference the resistors should all be the 56 or 68 ohm in your case...

Or follow this link and fill in the info

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

In your case it will be

6
5
20
5

BTW: the resistor can be on the + or - side, it make no difference...

 

[Talisen]

Thanks Flynn! I should hopefully be able to attempt this tonight or tomorrow.

BTW, is there a site that has a LED Calculator that can mix various voltages? (say I have 3mm 3v and 5mm 5v LEDs?)

 

[Darth Cross]

You can use Ohm's Law ( E=I*R or voltage = current times resistance) to calculate all the resisor values. Just subtract the LED voltage from the source volyage to get the voltage across the resistor.

For example 6v (source) minus 3v (LED) = 3v dropped across the resistor.

Put this voltage value into Ohm's equation with the current you need for the LED and it will give you the value of resistor.

R=E/I =3v/20mA = 150 ohms

Hope this helps a bit.

Richard

 

[exoray]

BTW, is there a site that has a LED Calculator that can mix various voltages? (say I have 3mm 3v and 5mm 5v LEDs?)

The only thing that changes is the value of the resistors, so just do them individual, as stated above using ohms law, or you can cheat and just plug the numbers into another calculator on that same site...

http://led.linear1.org/1led.wiz

 

[feek61]

You can try these links, they can be helpful:

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

http://metku.net/index.html?sect=view&n=1&path=mods/ledcalc/index_eng#