Led to battery pack?

Hi, I just bought a led (5mm) Infared and a battery pack but when i try to test the led it dont work? either i am doing it wrong or something i dont know lol....

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Toga_Dan2 years ago

http://www.newport.com/Infrared-and-Ultraviolet-Sensor-Cards/139709/1033/info.aspx simple,cheap,compact,robust. see IR.

verence2 years ago

You can't see the IR 'light' from the LED. But a digital camera can. The LED should show up in a pink/purple hue. Does not work with an optical finder (as e.g. some DSLR have). You just can use any mobile camera.

JustinM4 (author)  verence2 years ago

thanks ya all for the replies

caitlinsdad2 years ago

Infrared light is not part of the visible spectrum so you probably won't see the LED light up. Some may light up red but not all. You usually pair an LED with an appropriate resistor so that it does not burn out from the inrush of current from the battery. What kind of battery pack did you get, is it the right voltage for your LED and if it is rechargeable, charged up and if Lithium ion, do you have the proper low voltage shutoff circuit in there to prevent burnout and overcharge? You may have already toasted your LED if you just hooked it up to your battery, and you need to wire it up with the right polarity or leads going to the correct terminals on the battery. Use your digital camera or cellphone camera to view the LED when you power it up. The digital camera will pick up the IR light coming off the LED and you will see it on the screen. What were you planning to do with just an IR LED?

JustinM4 (author)  caitlinsdad2 years ago

well actually I have had that led sitting around it was new tho, thought I'd try to test it out. Wasn't actually trying to build something with that specific kind, btw is there an tutorial on which resistors go with wHich mm leds? Just got me a double A battery pack from RadioShack. Tho I am going to buy regular blue leds for trying to build an Ironman arc reactor

Look up any online "LED calculator". Input the specs of the LED and it should calculate the value of the required resistor and even give you a circuit diagram. Good luck.