With the help of this circuit you can change any LED Bulb into Emergency LED Bulb. This is a very simple emergency led bulb circuit diagram. Backup time of this led bulb is 4-5 Hr. We are using 3 1Watt White LED with this circuit normally 1 watt led is 3.2V and Current 300ma maximum. with help of this circuit all 3 LED’s will consume 500-600ma so 18650battery(2650mah) will give 4-5hr backup