Drawing amperes from leds
- Thread starter karlosk98
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LEDependent
Enlightened
Hoo boy. Yes, but be careful! LEDs are very sensitive to changes in voltage. For example, my Luxeon III LED draws 0.02 amps when I give it 2.9 volts. It jumps to 1 amp (the recommended maximum for a Luxeon III) at 3.9 volts.
I'd recommend setting up a "constant current regulator" to test this stuff out. That way, you can experiment with different LEDs and battery types without worrying too much about releasing the "magic smoke".
Battery capacity only specifies how long the battery will last, not its voltage characteristics.
I'd recommend setting up a "constant current regulator" to test this stuff out. That way, you can experiment with different LEDs and battery types without worrying too much about releasing the "magic smoke".
Battery capacity only specifies how long the battery will last, not its voltage characteristics.
Morelite
Flashlight Enthusiast
Increasing Vin (voltage supplied to LED) will increase the current, but that is not the best way to do it. The best way would be to use a regulated driver and select the drive level you want.
Start by understanding Ohm's Law:
http://www.the12volt.com/ohm/ohmslaw.asp
http://en.wikipedia.org/wiki/Ohm's_law
It's not as complicated as you might think by looking at these two URL's, but if you have little practical experience with "burning batt's, bulbs and wires".... now's your
chance! Just start out by playing around with cheap leds.
Simple answer: more volts through the led generally results in more current unless you have a supply circuit that has current limiting.
Now, go smoke some LED"s!
http://www.the12volt.com/ohm/ohmslaw.asp
http://en.wikipedia.org/wiki/Ohm's_law
It's not as complicated as you might think by looking at these two URL's, but if you have little practical experience with "burning batt's, bulbs and wires".... now's your
chance! Just start out by playing around with cheap leds.
Simple answer: more volts through the led generally results in more current unless you have a supply circuit that has current limiting.
Now, go smoke some LED"s!
erckgillis
Newly Enlightened
More current in a LED is dissipated as heat. As a diodes temp rises it will also allow it to draw more current. Without careful regulation and monitoring, more current raises the temp...which raises the current draw...etc. The LED cannot rise further or dissipate power as heat so...Poof!
E
E
Nocturnicus
Newly Enlightened
Welcome to the wonderful world of electronics! Like someone else suggested, there are some web sites where you can get yourself an introduction to Ohm's Law and the relationship between current and voltage. Check out your local bookstore, too. But then, watch out! Diodes are semiconductors, and they don't play by the rules. They cheat. The relationship between voltage and current in a normal resistive load are completely linear - apply twice the voltage to a resistor, and twice the current flows. But with an LED, or most any other semiconductor for that matter, the relationship is very non-linear: depending on what part of the LED's current/voltage curve you're on, a very small increase in voltage will result in a huge increase in current. Check out the specs given for LED's and you'll see that non-linear curve. But take heart; the information is out there, and it's fun learning. Enjoy!
Jay R
Flashlight Enthusiast
The battery capacity should not make a difference but in the real world it does. For example, a 800mAh cell may struggle to proide a current of 1 amp but a 3Ah cell may not have such a hard time of it.
