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 !