Skip to main content

Timeline for Signal LED delay mini-circuit

Current License: CC BY-SA 3.0

7 events
when toggle format what by license comment
Feb 4, 2014 at 21:42 comment added Spehro 'speff' Pefhany @angelatlarge It will not be especially bright (or especially dim) because it's getting current through the 330\$ \Omega \$ resistor. The apparent brightness of a single short pulse of "normal" brightness when perceived by a human eye will be very low. An oscilloscope and fast PIN photodiode/transimpedance amplifier would pick up a strong signal, but human eyes don't work like that.
Feb 4, 2014 at 21:39 comment added angelatlarge Oh, so you are not saying that while on the LED will be relatively dim? "and the LED will not be especially bright for that brief time" let me to believe otherwise.
Feb 4, 2014 at 19:47 comment added Spehro 'speff' Pefhany The LED will not appear to be bright, because the pulse length is (much) less than the human eye's "flicker fusion" time, so the apparent brightness is the actual brightness multiplied by something like \$t_{ON}/100msec\$. That ratio is about 0.003 (0.3%), so the apparent brightness will be miserably low.
Feb 4, 2014 at 19:30 comment added angelatlarge Would you mind expanding on the the claim that the LED will not be bright? I am not sure I understand the engineering/mathematical considerations behind this assertion
Feb 4, 2014 at 6:23 history edited Spehro 'speff' Pefhany CC BY-SA 3.0
clarified
Feb 4, 2014 at 6:17 history edited Spehro 'speff' Pefhany CC BY-SA 3.0
clarified
Feb 4, 2014 at 5:09 history answered Spehro 'speff' Pefhany CC BY-SA 3.0