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Old 12-25-2012, 11:16 PM   #11
xuyn2003
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Posts: 71
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Join Date: Jul 2011
Device: PRS-T1&KOBOTOUCH
Quote:
Originally Posted by DNSB View Post
Sheeshh,....

Their most likely method of controlling the LED brightness is using PWM. There will be no change in the flashing rate when using PWM as the brightness change will be done by modifying the amount of time the LED is on during each cycle.

If they are using PWM at 1KHz (a 1000 microsecond cycle width), I somehow doubt that anyone is going to notice any strobing effect or suffer any ill effects. Now if they were using between 5 and 30 pulses per second, you might have a case (and for the photosensitive epileptic, a seizure).

Say you are using a 1000 microsecond cycle and a resolution of 100 microseconds, you would get 11 steps from 0 microseconds on (dark) to 1000 microseconds on (full brightness) without having to change the cycle time.

Perhaps next time before getting angry, you should try getting educated?

Regards,
David
OK, I understand, the flashing rate will not change at different level, but the on-off time was adjusted in one cycle.

Another question, will PWM ,have a minimal on time limit? For example, it had to be on for at least 0.1 microsecond, if the time is less than 0.1 microsecond, it will not be turn on at all?
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