so you should pick up the next largest value of resistor to 6 OHMS (im not sure of the standard value) at at least 3/4W, for a 5V supply. It will be just as bright off of the 5V as the 12V, just for 12V your resistor will be dissipating much more energy (IE you will need a much larger resistance and much much higher wattage resistor) Resistance is inversley additive over a parallel circuit, but you dont need concern yourself with that. Take it as Linear just used a bunch of resistors to get the exact resistance value he needed through a "trick" with electronics. You can make due with a slightly larger single resistor, in series - as long as it meets minimum requirements. (at least 6 OHM and 3/4W)
according to the BT calc 6.8 ohms is the next standard step up. 5.9 ohms was the resistance spit out by the formula.
ok so I went back to ratshack once again, but they only had 5.6k-Ohm 1/2watt resistors in. The next ones up that they carried was 10-Ohm. So would any of these work?
come on some1 please....the 5.6 wont work and the 10 is not bright enough but I cant find the 6.8 anywhere....some1?
You can get 200 resistors from ebay for 2.99 pluss shipping in 10 packs of 20 resistors of ANY ohms you specify. Get a whole range and you'll have all you'll ever need.
HELLOOOOO OUT THERE? Mudslang, heres some advise, Correct me if im wrong, but first of all, if your running the resistor at 5 volts, there is going to be 1.5 volts drop across the resistor (3.5 v led voltage) Therefore the resistor will be dissipating about 1/2 a watt (.350 A X 1.5 V = .525 W) so ther resistor is gonna get pretty hot though it should work, a 1 watt resistor is a would be a good idea. at 12 v you get 2.975 W so you need a rather heavy duty resistor. Take a look here, and dont bother to buy wirewound, you dont need it, i think its for specialty stuff. Anybody know? http://dkc3.digikey.com/pdf/T033/0808-0810.pdf
OK this is for the LED n00bs (like me!) this link http://www.metku.net/index.html?sect=view&n=1&path=mods/ledcalc/index_eng has an applet that will calculate the required resistors for single or multiple LEDs and different power sources. Enjoy!
I used the calculator that BadOldMan posted.... 5v for the "Supply Voltage", 1.5v for the "Voltage Drop Across LED", but Im not sure what to put in for the "Desired LED Current"
