HOW TO CALCULATE VALUE OF RESISTOR FOR LED CIRCUITS
LEDs are becoming more and more popular for a variety of lighting projects and needs. This is due to the excellent power efficiency and extended life times of LEDs over incandescent lamps. Also, as the technology improves and production increases, the cost continues to be reduced.
LED is an acronym for Light Emitting Diode. This means that an LED has a specific polarity that must be applied to make it produce light. Failure to observe this polarity requirement will cause the LED to fail to light and could cause catastrophic damage to the LED. This is because an LED has a relatively low value of reverse polarity voltage that is allowed (normally about 5 volts). Since an LED is essentially a diode, it has a maximum current value that cannot be exceeded for any period of time.
Just watch the video to know the formulas.