LED Calculator v
I use this for myself, use at your own discretion!
Need a quick guide for what size resistor to use with a given LED? Use the form below...
LED Values
Source Voltage (Your DC power source)
LED Forward Voltage or choose by color below:
Color/Typical Voltage
IR 1.5v
Red 2.0
Orange 2.0
Yellow 2.1
Green 2.2
True Green 3.3
Blue 3.3
White 3.3
UV 3.3
Blue (430 nm) 4.6
LED mA Rating (25 is fairly safe if unknown)
Under drive LED by ~10%? (recomended for longer life)
Number of LEDs
Notes:
If there is liitle or no airflow around your LEDs run them at a lower 18-20ma instead of 25ma to avoid heat buildup and lengthen lifespan.
When soldering, use a low wattage (20-30w) soldering iron, LED's hate heat.