Hello,
I've been having some problems making a star projecting light box. I'm using a pair of these LEDs in series: http://www.superbrightleds.com/moreinfo/high-powered/vollong-3w-white-high-power-leds/896/
Their relevant specs are
Power dissipation 3W
Continuous forward current: 750 mA
Forward voltage: 3.6
The power supply that I have chose is a 9v 800mA supply, which should be more than adequate. I've tried a few different online calculators for resistance required in the circuit, and I came up with 2.4 ohm. I figured that I would be on the safe side and choose 3 10W resistors in series; this should give me 3.33 ohm (actual measured resistance is like 3.8).
The problem that I have been having is extremely excessive heat. The resistors are extrememly hot. I made the move to the excess wattage handling due to blowing an array of 1/4W resistors that totaled 3W of total dissipation. I'm a little new to circuit building and I have no idea what is going on. Please help!
I've been having some problems making a star projecting light box. I'm using a pair of these LEDs in series: http://www.superbrightleds.com/moreinfo/high-powered/vollong-3w-white-high-power-leds/896/
Their relevant specs are
Power dissipation 3W
Continuous forward current: 750 mA
Forward voltage: 3.6
The power supply that I have chose is a 9v 800mA supply, which should be more than adequate. I've tried a few different online calculators for resistance required in the circuit, and I came up with 2.4 ohm. I figured that I would be on the safe side and choose 3 10W resistors in series; this should give me 3.33 ohm (actual measured resistance is like 3.8).
The problem that I have been having is extremely excessive heat. The resistors are extrememly hot. I made the move to the excess wattage handling due to blowing an array of 1/4W resistors that totaled 3W of total dissipation. I'm a little new to circuit building and I have no idea what is going on. Please help!