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power supply 3V forward voltage 3.2-3.4 20mA. How many leds can i light up? Need a resistor for that, and how many OHM? Answered

i am a really beginner, i want leds in serial, and i can't figure out what resistor i need even with web calculator, i do not even know if i need a resistor please help me!



7 years ago

HI! friend ,
so you got 3volts! then you can light 3 led's with that but they will not glow bright and if you need more power you can add a capacitor you should use a 2200 micro farad capacitor and it should Be a dc capacitor ! and you don't need any kind of resistor be cause your voltage is low and resistant will decrease your voltage and a resistor is needed when forexample you have 5 volt's and you have to light only 1 led then you need a resistor case if you will supply 5 volts to a led it will make it hot and after sometime it will stop working ! if you have any more Questions you can mail me at samad@oniworld.in i will be always available there to help you don't be shy to ask! bye! bye!


8 years ago

Your power supply is too small, it won't light these LEDs properly.


Answer 8 years ago


Forward voltage is the ideal power supply voltage...at which you'll need to limit the current to 20mA with a resistor. for a 3.4v led, 3v will not light it effectively.