|
Welcome, Guest
|
TOPIC: Question about led...
Question about led... 11 months 3 weeks ago #71018
|
Hey ! I'm French and I building my own LightSaber with PVC pipe and other things ! I bought this Red LED on ebay :
Technical specifications : 100mA Wavelenght: 620-625 nm Luminous flux: 80-100 Lumen at 700 mA Forward voltage: 2.4-2.6 Volts Can you tel me what electrical resistance and power supply should I choose ? Some people told I had to use electrical resistance 1.6Ω/1.5W with Li-on 3.7V/3400mAh, on the other hand, I saw people use 4 cells LR06AA connected in series... I don't know what to do ! Can you help me out there ? Thanks ! 
|
Question about led... 11 months 3 weeks ago #71026
|
On a 3.7v lithium-ion, a 1.6 ohm resistor will just barely cut it, but you might want to go up to 2ohms to be safe, since the battery is 4-4.2v fresh off the charger, and these chinese LEDs are not great quality. A 1W resistor will meet minimum for calculations, but I will recommend a 2W.
If you do go with the LR06 / AA batteries (or LR03 / AAA), you will only need two of them in series with a 0.6-0.9ohm resistor. If you are good with math, resistor calculations are pretty easy. The formulas are: Resistance in Ohms: [Battery Voltage) - (LED Voltage)] / (LED mA / 1000) Wattage: [Battery Voltage) - (LED Voltage)] * (LED mA / 1000) |
Question about led... 11 months 2 weeks ago #71046
|
Kouri wrote:
On a 3.7v lithium-ion, a 1.6 ohm resistor will just barely cut it, but you might want to go up to 2ohms to be safe, since the battery is 4-4.2v fresh off the charger, and these chinese LEDs are not great quality. A 1W resistor will meet minimum for calculations, but I will recommend a 2W.
If you do go with the LR06 / AA batteries (or LR03 / AAA), you will only need two of them in series with a 0.6-0.9ohm resistor. If you are good with math, resistor calculations are pretty easy. The formulas are: Resistance in Ohms: [Battery Voltage) - (LED Voltage)] / (LED mA / 1000) Wattage: [Battery Voltage) - (LED Voltage)] * (LED mA / 1000) Thanks for your answer ! I know that this LED is not hight quality but it's just for a test ! Electrical resistance calcul is not the problem. But I would like to find the right number of Volt to provide the whole circuit. So for exemple, two Duracell LR06 / AA 1.5V with 0.9 ohm resistor it's ok ? How many Watt for the resistor ? Thank you again for your help !
|