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Seventeen milliwatts
Dec. 2nd, 2003 08:27 pmA blue LED, dropping 2.88V and consuming 5.93 milliamps, throws a visible circle of light a metre wide onto a ceiling two metres above it, and you get little spots in your eyes if you look directly at it.
This surprises me somewhat, particularly since I know the eye isn't all that efficient in the blue (I don't have a data-sheet for the LED, it came from ultraleds.co.uk and possibly their market is more "ooh, shiny blue thing to put on my tyre-rims" than the quantum fan, but hc/Ve gives 430nm); especially since the LED is specced to run up to 20mA power consumption.
I have a green one that consumes 5.27mA over 3.2V and lights the ceiling more brightly, though in a smaller circle; the red, 2.1V and something like 63mA, are a much brighter light. Also some infra-red LEDs, 11mA at 1.16V; obviously you can't see them lighting the ceiling, though I have a webcam that can detect them (to my slight surprise they appear white, so the colour filters on the webcam's CMOS must be uniformly transparent in the IR) -- but the webcam can't see the reflection on the ceiling, and I'm not sure if this is because the light is faint or the webcam sensor poor. And even a few UV LEDs, though I feel uneasy plugging them in (I don't have any obvious test for UV, and even 375nm light is not great for the eyes), so haven't.
Not quite sure why I picked now, rather than say fifteen years ago, to get interested in electronics again; I suppose I'm a bit less clumsy, significantly less prone to blowing components up to see the flash, and I feel more able to afford the components and the test equipment (though a multimeter nowadays costs £2.99). My vague hope is, with sixteen NAND gates, half a dozen 555 oscillators and a dozen LEDs of different bright primary colours, to be able to build an entertainingly flashy Christmas ornament -- though I probably don't have the craft skills to build a nice box to put it in.
This surprises me somewhat, particularly since I know the eye isn't all that efficient in the blue (I don't have a data-sheet for the LED, it came from ultraleds.co.uk and possibly their market is more "ooh, shiny blue thing to put on my tyre-rims" than the quantum fan, but hc/Ve gives 430nm); especially since the LED is specced to run up to 20mA power consumption.
I have a green one that consumes 5.27mA over 3.2V and lights the ceiling more brightly, though in a smaller circle; the red, 2.1V and something like 63mA, are a much brighter light. Also some infra-red LEDs, 11mA at 1.16V; obviously you can't see them lighting the ceiling, though I have a webcam that can detect them (to my slight surprise they appear white, so the colour filters on the webcam's CMOS must be uniformly transparent in the IR) -- but the webcam can't see the reflection on the ceiling, and I'm not sure if this is because the light is faint or the webcam sensor poor. And even a few UV LEDs, though I feel uneasy plugging them in (I don't have any obvious test for UV, and even 375nm light is not great for the eyes), so haven't.
Not quite sure why I picked now, rather than say fifteen years ago, to get interested in electronics again; I suppose I'm a bit less clumsy, significantly less prone to blowing components up to see the flash, and I feel more able to afford the components and the test equipment (though a multimeter nowadays costs £2.99). My vague hope is, with sixteen NAND gates, half a dozen 555 oscillators and a dozen LEDs of different bright primary colours, to be able to build an entertainingly flashy Christmas ornament -- though I probably don't have the craft skills to build a nice box to put it in.
