Running the LEDs at rated current will make them a flashlight
20ma thru a superbright LED IS A FLASHLIGHT.
The blue ones usually come on at 3.1 volts,
The red ones start at about 1.9 volts.
2 to 5 ma is plenty.
Red, yellow, green are the best for 3.7 volt mods.
And yeah, it has been great, thank you so extremely much for everything you have provided me with, and you're little test8-o Felt just like I was back in school again with my notebook busted out and answering trick questions. Never thought I'd miss learning so much.
But alrighty then, guess I know what my next step is, back to the drawing board! Errrr... MS Paint...
TBH I only made it 470 Ohms because that's what MadVapes sells.. lol. I actually did some research into LEDs and learned how to calculate the resistor value.
Resistor value for an LED (in Ohms) = (Power supply voltage LED voltage drop) / LED current rating
I think green LEDs typically have a forward voltage of 2.1, and I'll probably want to put about 20 mA through it. Using a 3.7V battery setup the resistor I would need is:
R = (3.7V-2.1V) /.02A = 80 ohm
The nearest rated resistor acording to ledcalc.com is 82 ohms. I'm surprised how much less than 470 that is. Why is everyone using 470 ohm resistors for their LEDs??
Blue LEDs require even more voltage (typically 3.4 I've read) so we'd need to use an even smaller resistor (18 ohm).
These numbers seem small.. am I doing something wrong?
As was mentioned most just want an indicator, not a flat out light. I had picked up a number of blue/red bi-color 3mm LEDs. I run the blue side with a 470Ω (3.7v mod) and it's just right for my needs. I would not want it any brighter. Pretty much like a Joye battery.
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