2022年6月1日 · What I need is basically the luminous efficacy of the LED (luminous flow/radiant flow). At this point I am quite sure the provided data in the datasheet is not enough to calculate that number. My rough estimate of those LED is a luminous efficacy of 300lm/W which results in a energetic efficacy of roughly 40%.

2010年5月21日 · For an LCD TV the backlight LED gives you the ligth source - the only reason for using LEDs rather than flourescent lamps is the smaller size, greater efficency and longer life. A single pixel only puts out one color (red,gree or blue) groups of three or four pixels are used to give all the colors by varying amounts of these primary colors.

2004年7月9日 · Place your hand against the television screen, with the television off but the lights in the room on. Close your eyes and cover them with your free hand so that you will have good night vision when the lights go off. Turn off the lights, remove your hand from the screen, and look at the screen. You will see a ghostly after image of your hand there.

2019年1月16日 · But I'm struggling to understand why the FitBit uses both Green and IR LED whereas the sensor at the receiving end is only for IR. All the theory I read suggested that there is a Green (or Red) LED and an IR Sensor. So if there is an IR Sensor, why not use only an IR LED instead of Green (or Red) plus IR LED. Any insight would be grateful...

2025年2月7日 · Using your LED, the easiest thing to do is place the LED a couple of meters (or more) away from your slides. Yes, the intensity will be low and you will need to be in the dark. If you know how to produce a collimated beam using your LED, you'll get brighter results.

2024年12月21日 · This is sort of a sister thread to my other thread. But I've bought a spectrometer and have been playing around with it. I pointed it at the sun on a clear day and got as expected a nice full spectrum of color with a large spike of blue: 1. My first question is.. is the spike in blue range...

2024年12月22日 · The research was conducted in the laboratory of Markus Meister (PhD '87), the Anne P. and Benjamin F. Biaggini Professor of Biological Sciences, and it was led by graduate student Jieyu Zheng. A paper describing the study appears in the journal Neuron on December 17. A bit is a basic unit of information in computing.

2024年10月16日 · It would be interesting if we had tunable type monochromatic LED's, so that the picture we see on a TV screen could be made from many monochromatic sources all on the perimeter of the CIE chart, rather than the broadband LED's (whose components also come from the perimeter) whose color coordinates are then a point near the perimeter, with a ...

2012年1月13日 · Try googling "CR" and you'd understand my frustration ;p I'm not sure if Cell Relay would be appropriate - the voltage is an analog signal, although the circuit that controls the relay is probably digital.

2009年7月25日 · Also fun: playing with an optical chopper to produce visual difference frequencies. Tune the chopper to a multiple of 60 Hz and look at an analog oscilloscope screen through it, and you see a number of stationary dark regions on said screen. Detune it a little bit, and that region flickers at a rate given by the difference frequency.