
LEDs and External Quantum Efficiency (EQE), how to find Light …
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 …
infrared - Help me calculate spectral irradiance of an LED from a …
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 …
Creating a new power source for light-string ornaments
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 …
voltage - What destroys a LED in the reverse direction? - Electrical ...
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 …
How to estimate LED lifetime? - Electrical Engineering Stack …
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 …
ohms law - Why do we need resistors in led - Electrical …
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, …
How to choose right PWM frequency for 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 …
How efficient are LEDs? - Electrical Engineering Stack Exchange
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 …
diodes - How do I model an LED with SPICE? - Electrical …
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, …
Why is PWM used to control LEDs even when they're only used On …
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 …