Bob asks | Any websites you would recommend for diy led ringlights? | | Now I'm off to do a dogpile search..... | How's dogpile these days? I have to confess Google drew me away from the metesearch engines .. here's a few pages: http://led.linear1.org/a-cheap-current-regulated-luxeon-star-driver-design/ this Luxeon manufacturers page has a resistor calculator built in: http://www.luxeonstar.com/basic-circuit-design.php LED's are best driven by a constant voltage with a regulated current to achieve the colour emission desired (details are available on the Luxeon site for all their LED's), varying the power changes the colour behaviour - to get more light you add more LED's, less light, either switch some out of circuit OR you have to look at 'pulsing' them. This is done with what is described as a pulse width modulator which pulses the correct current and voltage to the LED and varies the frequency of the pulse. The very first LED circuit I built pulsed the LED for two reasons, I was driving a 3.7V LED with a 1.5V power source so I basically needed the design to invert and boost the power and secondly, I believed a boosted pulsed current could produce more light. It can, but again, the colour temperature changed so I dropped the whole idea of pulse width modulation and settled on simpler circuits. another circuit: http://www.instructables.com/id/EAI4SP8967EWIJMLTT/ more: http://www.bluehaze.com.au/modlight/Luxeon.htm k
