Infrared detectors and transistors

[Fredinappolis]

Does anyone know any good websites that talk about how an infrared detector and emitter from Radioshack works? I don't understand the theory behind it. I also am wondering about how transistors work. My circuit that I am working on has an NPN resistor in it. As far as I understand, that means that if the base has a positive charge to it, then a negative charge will flow through the collector and emitter. Is this right? Can you expound any more than this?

[vascop]

Have a look on the internet for goodness sake!

[mibn2cweus]

In an NPN transistor a small control current flowing from emitter to base provides charge carriers that enable a proportionately larger current flow from emitter to collector.
A PNP transistor works similarly but with currents flowing in the reverse direction.

http://www.allaboutci...m/vol_3/chpt_4/1.html