T tommylee New Member Jun 24, 2013 #1 Can anyone tell me how to reduce a 6volt lantern battery down to 3.5 volt for a led light? Thanks
MikeMl Well-Known Member Most Helpful Member Jun 24, 2013 #2 A single resistor will do it. How many mA is the LED rated for? How bright do you want it?
Mosaic Well-Known Member Jun 24, 2013 #3 Check spec. for LED Vf , eg 2V Check spec for continuous forward current eg. If=20mA. Calc 6-2 =4V Calc 4/.020 = 200Ohms. Use a resistor in the 220 Ohm to 330 Ohm range based on brightness desired (smaller is brighter)
Check spec. for LED Vf , eg 2V Check spec for continuous forward current eg. If=20mA. Calc 6-2 =4V Calc 4/.020 = 200Ohms. Use a resistor in the 220 Ohm to 330 Ohm range based on brightness desired (smaller is brighter)
T tommylee New Member Jun 24, 2013 #4 Mike it is a 20ma and voltage is 3.2 thru 3.8 as fare as brightness I dont care, as bright as it turns out will be fine. thanks for your help.
Mike it is a 20ma and voltage is 3.2 thru 3.8 as fare as brightness I dont care, as bright as it turns out will be fine. thanks for your help.
T tommylee New Member Jun 24, 2013 #5 Mosaic, so a 220 to 330 wouldd get me in range of 3.2 to 3.8 volt ?? Its a 20ma LED
alec_t Well-Known Member Most Helpful Member Jun 24, 2013 #6 so a 220 to 330 wouldd get me in range of 3.2 to 3.8 volt ?? Click to expand... You don't set the voltage; you set the current (by choice of resistor) knowing Vbattery and the Vf range, as Mosaic explained. 220 will be fine in this case.
so a 220 to 330 wouldd get me in range of 3.2 to 3.8 volt ?? Click to expand... You don't set the voltage; you set the current (by choice of resistor) knowing Vbattery and the Vf range, as Mosaic explained. 220 will be fine in this case.