A bipolar junction transistor (bipolar transistor or BJT) is a type of transistor that uses both electron and hole charge carriers. In contrast, unipolar transistors, such as field-effect transistors, only use one kind of charge carrier.
Google Map of 2017 Total Eclipse in Nebraska. Google Map of 2017 Total Eclipse in Nebraska. (Click to use interactive map) The map above links to an interactive Google map showing the visibility of the Total Solar Eclipse of 2017 Aug 21 in Nebraska.
The next good solar eclipse visible from Pennsylvania will be on 21st August 2017 when a large partial eclipse occurs (80% of the Sun's diameter obscured at maximum). This eclipse will be seen as total along a line from Oregon to South Carolina.