This information is now available in my "Beginners Guide to Electronics" book. 
Caravan
Visual If you find this information useful and want to thank me, why not buy one of my low-cost "virtual books" that you can download direct to your computer? My books can be read on-screen or printed out on paper. They are full of colour photos and illustrations. Click on "Books", above, for more information.
How do Transistors Work?
What does a transistor look like?