Super Bright White 5mm LED (25 pack)

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AlissaHowe
 
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Joined: Thu Jun 04, 2015 9:19 am

Super Bright White 5mm LED (25 pack)

Post by AlissaHowe »

I bought a pack of these to use in a presentation with preschool teachers on how they can bring science into the classroom. I had them use a 9volt battery to light them up using wires, etc. The bulbs were burning out and the wires were getting hot and smoking. Was the 9volt battery to much power for this small bulb? We had a presentation done FOR us with the exact materials, except the bulbs ordered from you were a bit larger - we didn't have any of those issues.

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Franklin97355
 
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Re: Super Bright White 5mm LED (25 pack)

Post by Franklin97355 »

From the product description: 3.0V Typical Forward Voltage, at 20mA current.
LEDs are current devices and if not regulated will take all the current available to the point of self destruction. You need to limit the current available to the LED, usually by using a resistor. If my math is correct you would need a 450 ohm resistor in series with the LED but I'm sure one of the other techs will correct me if I'm giving you bad advice

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AlissaHowe
 
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Joined: Thu Jun 04, 2015 9:19 am

Re: Super Bright White 5mm LED (25 pack)

Post by AlissaHowe »

Oh my. I was just using playdough as a conductor and then the black plastic piece with the red and black wires that attaches to the top of a 9 volt battery. Then lighting the LED by sticking the two ends into the playdough - one side that was touching the black wire, and one side that was touching the red wire. I feel way out of my league here.

PS this is an activity for young children to do.


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