I just got an 18 1w white batwing LED flood board. Check this out And I don't know if I want to build a light for my house or a SUPER flashlight. If I were going to build it for my house I would like to be able to plug it into the wall. So, does anyone know what to use to make it work on AC? Or would you build a huge floodlight flashlight? [img]/ubbthreads/images/graemlins/grin.gif[/img]
Are those connected? In series or parallel? 18 in series would give you about 60v as what you would have to use (Vf) to light those up properly. Vf x 18 =3.4v x 18 = 61.2v. You don't need a wall wart or a transformer, you can just use a diode. You need a diode that can handle 1w or more (they are in series). But wait, you have a hand full of diodes!!! Does anyone wonder why they used 18, instead of 20, or 15????
There's just one thing I'd check out before you plug it in. How much reverse voltage can these diodes take? Note that PEAK voltage @120vAC is 167v. Allow for at least 10% over. I'd want them to be able to take 200v or more........
That's about 11 volts reverse voltage capability which is probably pushing it for something not designed for this. But, they did build it with 18 diodes, wonder why? They also sold it......
Careful there Russ. Last time I read about, some of the LSs have a reverse-parallel diode built in for protection. Also, a bridge rectifier is peanuts to the price of a luxeon.
However, a 7.5uF 250V capacitor and a 33R 5W resistor in series with the input to the bridge would give you a bare-bones means of running hte array. Yes the resistor will get warm, but is necessary because the time the switch is thrown is uncertain. If you have an optoisolator triac driver handy, most of these have a zero-crossing detector that makes the resistor unnecessary.