Passengers talk about the Pennsylvanian, an Amtrak passenger train that runs between Pittsburgh and Philadelphia. It was announced that the line may cease in October of 2013. (Video by Michael Henninger; 2/17/2013). think it would be worth it for Amtrak and PennDOT to see if more schedule diversity might make it a more popular travel option, Ms. Katchmar says. â¢ Go to post-gazette.com for a slideshow of photos taken aboard the Pennsylvanian and a video report. Jon Schmitz: jschmitz@post-gazette.com or 412-263-1868.
A light-emitting diode (LED) is a semiconductor device that creates light using solid-state electronics. A diode is composed of a layer of electron rich material separated by a layer of electron deficient material which forms a junction.
How They Work. Connecting a diode to an electrical current excites the electrons within the diode, making them release photons, which we see as light. The color of the light is a direct result of the energy gap in the semiconductor of the diode.