LED Selection HELP

[Helios]

I caught the laser bug first but now I am becoming interested in other electronics including LEDs. (Kind of a backwards progression I know)

Ive tried to search for a page explaining the differences between LEDs and what criteria to use to judge them by but I keep just getting information on LED TVs

As for selecting LEDs whether they be 3mm, 5mm or Cree etc what information should I be looking for?

ALSO any other good LED information sources or pages would be greatly appreciated.

Thanks


EDIT: Also if I have some misc. LEDs left over from flashlights how can I determine what kind of current and voltage they require?

 

[shhh]

You looking for info for led flashlights or for automotive applications?

This image shows a layout for regular leds in strings.
Connected +-+-+-+-
LED series parallel array wizard
Is a led calculator in which can help u chose your resistor based on your info
for your leds ect...

Your higher watt emitters will need drivers as to resisters to keep current constant if i remember right.

 

[Cyparagon]

Most LEDs need around 3.6V. Any 3-5mm LED can take about 20mA. The wattage rating is a rough corollary to brightness, and lumen rating is a direct corollary to brightness.
I'm not sure what else you're looking for :undecided:

CPF is probably the best LED place.

 

[Helios]

I'm looking to just tinker. I want to build an led light strip to go above my 90gal fish tank and I'm just not sure how to select the appropriate leds or make the misc. leds I have work correctly in an array.

 

[HIMNL9]

Do you mean light strips ? ..... like the ones that PA sells in 5 meters rolls ?

They have them already made, waterproof, and also RGB with controller and remote control (and also an 1 meter version, if i recall correctly), and DX sell something similar too ..... i'm not sure how much long you need the strip, or if you want it color changing or not, but those strips may be an alternative to DIY, if you want then small (being SMD, i mean), and also they can be cutted each 10cm.

For DIY, i suppose you can choose whatever you want in fact of colors and powers, only you have to make them waterproof (water and electricity does not match good, and if the fish tank is salt water, also corrosion must be kept in consideration.

 

[shhh]

DIY LEDs - The write-up - Reef Central Online Community


here is a link to a guy that did a led light on his tank with 48 cree leds
24 white 24 blue. It is back from 09 but still shows u something.

 

[BShanahan14rulz]

LED series parallel array wizard

 

[Benm]

Just measure it yourself! see what your leds drop at the desired current, and then build circuits accoredingly.