2015年4月28日 · I needed to find the Light output power (LOP) and divide it with the input power to give the EQE, as EQE = Output Power / Input Power. This is not the usual definition of quantum efficiency. Quantum efficiency should be a ratio of numbers of quanta. For an LED this would be $$\frac{\mathrm{Photons\ emitted}}{\mathrm{charge\ carriers\ injected}}$$

I have an infrared LED that emits light at 940 nm, and the manufacturer claims it's about 1000 mW/sr. While the light is not visible to human eyes, light of this wavelength can damage human eyes if it is strong enough. The following equation can help me determine if …

2011年11月28日 · Constant current supply: Am LM317 IC can be used to provide a simply built constant current feed. A "problem" is that the circuit "uses up" a minimum of about 3Volt to operate.

2015年5月31日 · When a LED is included in a circuit that applies a reverse voltage that exceeds the reverse breakdown, a reverse current can flow and the LED might be destroyed. But what is it that actually destroys the LED: is it the reverse voltage itself, or is it the reverse current that is made to flow, or is it simply the overall power dissipation caused ...

2023年12月20日 · A Japanese made JVC stereo has lost the LED backlight for the small LCD display (it's a couple 5mm LEDs). I've see failures of HP dot matrix LED display (albeit rather old ones). On the other hand, I've had quite good luck with …

2012年3月20日 · An LED is a diode made from a semiconductor material which generates photons of light when current flows through the material. The more current through the LED, the more light the LED will emit, the brighter it will be. However there is an upper limit which is the amount of current sufficient to damage the LED.

2013年8月18日 · \$\begingroup\$ I am currently experimenting with dimmable LED lights installed in a living/eating area indoors. Setup right now is a LED dimmer Leviton and dimmable LemonBest 4W LED spot light. At lower dimmer settings there is a bad flicker. It's at 120 Hz (2 zeros per wavelength) and it generates a stroboscope effect.

2017年8月25日 · The luminance efficacy is different for different LED colors. For a blue LED, this it is about 90 lumen/W depending on its peak wavelength. The luminous efficiency of the LED bulb is about 70 lumen/W due to light being trapped or absorbed in the chip package, bulb package and power loss conversion from AC to DC.

Adding to W5VO's great answer, I somewhat streamlined the process for myself the following way: I used the chart type of XY scatter plot as lines only on OpenOffice (YMMV with Excel, etc.) and set the minima and maxima of the axes manually, e.g. (X,Y)=(1.4-4.0, 0.01-50.0), to pervent it from autoranging to outside the scope of my sampled data.

2015年4月10日 · When a short-cycle pulse voltage with a frequency of approximately 60Hz is applied to an LED at a duty ratio of about 5%, the LED looks about twice brighter [sic] to human eyes than that driven by a direct voltage, the research group said. - Nikkei Technology - Human Perception Studied to Double LED Brightness