How do transistors work?
NOTE: This is an older web site and some information is out of date. If you see something you wish to order, please go to the new web site and see the catalogue there. You can not place an order on this satcure-focus site. Return to SatCure-Focus Home page. Thousands of textbooks have been written to explain electronics and I haven’t found a single one that can explain the operation of a transistor. They all make it seem so complicated! Let’s see if I can do better. Here is a picture of a transistor. My transistor runs on water current. You see there are three openings which I have labelled “B” (Base), “C” (Collector) and “E” (Emitter) for convenience. By an amazing coincidence, these also happen to be the names used by everyone else for the three connections of a transistor! We provide a reservoir of water for “C” (the “power supply voltage”) but it can’t move because there’s a big black plunger thing in the way which is blocking the outlet to “E”. The reservoir of water is called the
Most introductory textbooks do a very poor job of explaining the details of how transistors work. First they assume that the Base current is somehow controlling the Collector current, then they try to explain how one current can affect another. These explanations always fail because Bipolar transistors, like FETs, are voltage-controlled devices. One current doesn’t affect another. Instead, the Base-Emitter voltage controls the thickness of an insulating “depletion layer” which lies in the path of both the Collector current and the Base current.
