The water pipe analogy has been used for a long time to represent current flow thru a pipe. I want to expand the water analogy a little further. Bare with me.
Have you ever seen this? Do you know what it is? It is a simple and effective way of measuring water flow. It is also a very good analogy of how a semiconductor junction functions.
This is a smaller version of the same device. The principal of operation is based on the relationship of pressure and cross section area of the conduit to flow. Consider the flow thru a 1 square foot conduit and a 2 square foot area with the same pressure producing it. Doubling the cross sectional area would produce twice the flow if all other factors are constant. The device is a flume. The flow is produced as water overflows the gate. the more flow there is the higher the water level will be. You can see the water is higher than the lip and it is free falling as it overflows. In this case the water overflows the flume at a rate determined by the pressure it produces as it rises in the ditch feeding the flume. A self regulating process? Well if it starts raining the flow will pick up because the feed will increase and the level will adjust itself. (self regulating based on the feed rate.
This view shows the operation more clearly. Notice the measuring scales. They are basically bronze rulers that read the water height. The main thing here is overflow. The water flows from a higher level to a lower level.
This is another flow measuring device with a much different operation. It is an underflow.Y1 and Y2 are used to determine the flow. The question is how does this relate to a transistor junction operation? Hopefully the next post will reveal that.
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