An LED and a semiconductor laser (or laser LED) work in essentially the same way, that is, light is emitted as electrons and holes combine, with emission wavelength dependent upon the materials used. But while LEDs emit light in a narrow spectral range ...

Color digital laser and light-emitting diode printers are very similar. Both can print your business documents relatively quickly by melting toner to the paper, and both use a photosensitive drum. The difference between the two printer technologies lies in ...

The restriction initially prohibited all aircraft operations in El Paso to shut down for 10 days. Here's what we know about what caused the closure.