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chamenos said:
don't mind me but what's PWM voltage regulation? /ubbthreads/images/graemlins/confused.gif
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It means having a circuit to switch the power to the bulb on and off very very quickly and for only a preset amount of time depending on what voltage is set on the PWM circuit and the input voltage. Input voltage has to be higher than output voltage. E.g.
I have 12 volts SLA, a 6 volts bulb. The circuit if set to 6 volts, will supply power to the bulb 1/2 the time because 12/2 = 6 . In that sense, the bulb only see 6 volts. If the SLA drops to 8 volts after some time, it will be 0.75 percent of the time because 8 x 0.75 = 6 volts. This doesn't work with LED because the LED sees the full voltage that it has been fed and will draw a current equivalent of what it will take if driven at the voltage all the time nt with whereas with a filament, the filament takes time to heat up and thus, if you off the power half the time (like in the above example of 12 volts input, the filament will cool down enough for it not to melt. The pulsing of the voltage is done at very high speed so you don't really see it flickering. something like a few megahertz. Hope I've help you understand a bit of what's going on. I don't really have good explaination skills so pardon me. /ubbthreads/images/graemlins/smile.gif