Flash Light Project (Feb 08 N&V)
Posted: Tue Feb 26, 2008 8:46 pm
I have been reading the Flash Light Project article in N&V Feb08, and am wondering if someone else who might have read same could field a question? I am a total newbie, so this may be a dumb question, but here goes.
The author states that if 5-10 LEDs are used that R2 is not longer needed. I am having trouble following this? Assuming that the output voltage is 30V (as he later suggests), I can understand why a current limiting resistor would not be necessary with 9 LEDs were uses, as the aggregate forward voltage for the LEDs would exceed 30V. But if 5 or 6 LEDs were used, this would not seem to be the case?
Please note, I am by no means suggestion that the author's analysis is incorrect. I realize I am missing something and hope some can point me in the right direction.
Thanks.
The author states that if 5-10 LEDs are used that R2 is not longer needed. I am having trouble following this? Assuming that the output voltage is 30V (as he later suggests), I can understand why a current limiting resistor would not be necessary with 9 LEDs were uses, as the aggregate forward voltage for the LEDs would exceed 30V. But if 5 or 6 LEDs were used, this would not seem to be the case?
Please note, I am by no means suggestion that the author's analysis is incorrect. I realize I am missing something and hope some can point me in the right direction.
Thanks.