3 volt Nengliang LED lamp
LED is a constant current source, voltage is 3V, upstairs is nonsense, 0.7V pressure drop is diode, and LED does not matter (although LED is a light-emitting diode).How much 3V can light LED depends on the input current, the small power LED current of about 30mA of the rated current, generally used in 20mA, in order to extend the life.
The key depends on the current strength.
Look at what kind of LED lights, LED lights on the voltage is different, the number of LED lights can also be different, the small LED lamp voltage is 0.7V, so that probably can bring up 4. If the high power LED lamp voltage is probably 3.3V, the 3V voltage can barely carry one.The premise, of course, is that the output power is large enough. That is, the output current can be large enough to achieve the rated brightness
