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Sep 6, 2016 at 12:32 comment added Scott Seidman Yes- but reader's should know that this is a rough approximation. $V_b$ is generally not much bigger than $V_f$ -- more often, it's bigger by a factor of 2-5, as $V_f$ is about 2V, depending on color. If you get an LED with a resistor built in, designed to be used with 5V, you may not get near enough to $V_F$ to light two in series.
Sep 6, 2016 at 11:31 history edited Ariser CC BY-SA 3.0
contradiction removed.
Sep 6, 2016 at 11:29 comment added KalleMP Your answer contains a bit too much generalisation in the text if one is working with combined voltages close to the LED forward voltage. a 3V LED + resistor combination will not work well at 1.5V or 6V but a 15V LED + resistor combination will work from 5V to 15V in the manner you hope. I gave you an upvote for "(nearly)".
Sep 6, 2016 at 10:57 history edited Ariser CC BY-SA 3.0
formatting corrected
Sep 6, 2016 at 10:47 comment added Ariser @ScottSeidman: thanks for the correction. Better now?
Sep 6, 2016 at 10:46 comment added Ariser @pjc50 That's why I wrote \$V_b >> V_f\$. I didn't want to extend it to n LEDs then :)
Sep 6, 2016 at 10:45 history edited Ariser CC BY-SA 3.0
corrected wrong statement. Thanks to @ScottSeidman
Sep 6, 2016 at 10:38 comment added Scott Seidman This is incorrect, until you change "reduced" to "approximated".
Sep 6, 2016 at 10:38 comment added pjc50 This is true, but relies on Vb > 2Vf, i.e. most of the power being spent in the resistors in the normal use case.
Sep 6, 2016 at 10:26 history answered Ariser CC BY-SA 3.0