I cannot find anything on this ANYWHERE on the internet, so I'm posting it here. I bought a bunch of 20cd 3.2-3.8V 30mA white LEDs, and a ton of 56ohm resistors. I connected each LED with a resistor, repeat 12 times, all in parallel. The source is 5V. (USB) Each LED gets 3.3V, good enough, but the source is now down to 4V.
(a USB phone charger I had lying around - the more I add to it, the lower the voltage gets) The odd thing is that my multimeter tells me the LEDs are pulling around 108mA (yes, for 12 of them - the current seems to be proportionality less as I add more LEDs, as it was 24mA with one, 40mA with two, 55mA with three, etc), and the adapter is rated for 700mA, so this should not be an issue. My watt meter (120V) isn't even detecting this, so I don't think I'm shorting it (I know it'll detect 3W or so of draw, for instance). Any thoughts?
Note: I'm doing this on a breadboard at the moment, but will eventually be soldering it together. I already drilled some holes in one of those plastic CD protectors that come in a pack of CD-Rs or DVD-Rs for the LEDs.
This post has been edited by LiveBrianD: 21 November 2012 - 04:50 PM