5V power source
white LED operating voltage 3.2V, I = 0.15A (150mA)
voltage of resistor (U) V=5V-3.2V=1.8V
resistor to be chosen R=V/I=1.8V/0.15A(150mA)=12Ω 1/2W
power of resistor to be chosen P=UI=1.8V*0.15A=0.27W (normally we will choose 0.5W two time more than that of calc. value)
7 parallel of 5730 use 7 12Ω 1/2W resistor
parallel each LED with many resistors
for 3020 smd led 3V battery
R=V/I = 3V/0.02A(20mA) = 150Ω
series of 7 LED with one resistor
LED: 0.02A(20mA)
5V charger to 3V operation
(5-3)/7LED x 0.02A = 14.28Ω