Buy Online UNIVERSAL HUB 5mm Round LED Light Emitting Diode High Brightness. (5mm yellow, 100) from IndianLogisticsInfo.Com in Association with Amazon India
Each LED should have a 'Forward Voltage' label that specifies the amount of voltage needed to carry power and create light.
You can power any of the 5mm LEDs except the reds and yellows without bothering about keeping track of the current.
The current ratings of 5mm LEDs are substantially lower, often around 15-30mA, and we may limit the current by connecting a resistor to the LED.
Input Voltage = LED Vf + Resistor Voltage Resistor Voltage = Input Voltage LED Vf Voltage Across Resistor = 4.5V 3.4V
5mm LEDs brightness is usually measured in millicandelas (mcd), but there is much more to this than just putting a certain number of brightness on any LED.