Can i use 3 leds (20-30 mAh, 2,8-3,4 V) with a 3 volt battery?Do I need resistors?

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Like L says, they'll light, but they won't get 20-30mA flowing through them, so they won't be full brightness.
Popstickal (author)  steveastrouk7 years ago
Is it smarter to get 2*3V battery = 6V and then use a resistor to limit the current to 3,2V and then use 3 led´s?
Would I get full brightness then?
And can you say witch kind of resistor I should be using?

Is it smarter to limit the current to 3V instead of 3,2, then the led´s should survive longer.But I guess they wont be as bright.

I want to build a flashlight white these 3 led´s and make them bright, can you help?

You don't limit the volts, you limit the current. The volts take care of themselves. Do these LEDs say they have a 3.2..3.6 volt forward drop ? Yes, you'd be better with a higher voltage and a resistor - you'll get full brightness that way.

Popstickal (author) 7 years ago
But how do I get 20-30mA flowing between them?

Okey I have new led´s.
3 led´s with ( 3,2~ 3,6).
If a use a 6 V battery and use a 150 ohm resistor I would get 3,4 V.
Is it , good?
Would it be full bright for a flashlight?
lemonie7 years ago
They'll be 20-30mA (no H).
Above 3V I wouldn't think so, 2.8 to 3 you should be OK, and without a resistor (unless these are expensive and you don't want to take risks?)