Transistor current flow

[Chassis]

Can someone please explain to me how Transistors work. I understand that it gets used as switches and amplifiers. what confuse me is eg a NPN transistor,does it only operate when +tve gets place to base and only -tve into collector and out at emitter .will it operate when you put -tve to base and +tve into collector to emitter? Or can someone please send me a link that can make if very clear how the current flow through both transistors.

 

[Harald Kapp]

Try this one - out of a huge list of Bing hits.

We also have a ressource on this topic (I think it is work in progress).

 

[Chassis]

Harald! Thanks a lot I Finally got it