The flow of electricity and the flow of money in an economy share a lot of common rules. The following hypothetical economic arrangement between three countries can share the behavior of bipolar transistors.
Say there are three countries in which use two use $ as a currency and the third country uses # as their currency. Suppose One country has an abundance of $. Call this country Surplus_Land. Suppose the other country has a shortage of $. Call this country Want_Land . Now suppose the third country which uses # happens to be right between the two other countries. Call this country Between_Land. The arrangement of the three countries is shown below
Between_Land
_______________________________________
|$$$$$$$$$$$ | # # | $ $ $|
|$$$$$$$$$$$ | # | |
|$$$$$$$$$$$ | # # | $ $ $|
|$$$$$$$$$$$ | # | |
|$$$$$$$$$$$ | # # | $ $ $|
|$$$$$$$$$$$ | # | |
|$$$$$$$$$$$ | # # | $ $ $|
|____________|__________|_______________|
^ ^ ^
Surplus_Land /_\ /_\ /_\ Want_Land
| | |
depleted regions
Now Between_Land would have just precisely the right amount
of # for its economy if it did not have neighbors. If
there are no currency barriers at its borders, some of its
# are going to makes their way across the borders and will
not be coming back. So there will be regions at the borders
which be depleted of #. The need created by the absence
of # will continue to grow until it finally stops the flow of #
across the borders. So a natural
currency barrier develops at the borders due to the vacuum of
currency left as currency is lost across a border.
Consider the # to be like an bill for a $ such that a $ can completely cancel the debt of a #. Want_land will see some of its $ migrate across the border too. The depleted region within Want_land is experiencing a shortage of $, and will try to hold in its $. But since a # is a bill for a $, the depleted region will resist # to keep from going even deeper in debt. So the barrier in fact prevents currency travel in both ways.
Now suppose the the ruler of Between_Land decides he is going to start printing some money. Say this rate is one # per second. Where does this money go?
Between_Land
_______________________________________
|$$$$$$$$$$$ | # # | $ $ $|
|$$$$$$$$$$$ | # | |
|$$$$$$$$$$$ | # # | $ $ $|
|$$$$$$$$$$$ | # | |
|$$$$$$$$$$$ | # # | $ $ $|
|$$$$$$$$$$$ | # | |
|$$$$$$$$$$$ | # # | $ $ $|
|____________|__________|_______________|
^
Surplus_Land /_\ Want_Land
|
one # per sec
The new money is going to reduce the shortage and thereby
lower the barrier at the borders. But at the Want_land border
there are two barriers while there is mainly only one at
the Surplus_Land border. This is where that extra # will go.
The carrier barrier at the Surplus_Land is the lowest and easiest
to lower to the point that 1# per sec flows across it and is lost.
Between_Land
_______________________________________
|$$$$$$$$$$$ ->$ # # ->$ $ $ $|
|$$$$$$$$$$$ ->$ # ->$ |
|$$$$$$$$$$$ ->$ # # ->$ $ $ $|
|$$$$$$$$$$$ <-# # | |
|$$$$$$$$$$$ ->$ # # ->$ $ $ $|
|$$$$$$$$$$$ ->$ # ->$ |
|$$$$$$$$$$$ ->$ # # ->$ $ $ $|
|____________|__________|_______________|
^
Surplus_Land /_\ Want_Land
|
one # per sec
The one # per sec is flow is going to reduce the barrier to
Surplus_land until it can flow can cross the border. But
lowering the barrier for the # does the same for the $.
If the $ of Surplus_Land is 100 times more abundant, then
there will be 100 $ crossing over going the other way.
If Between_Land is thin, all of those $ are going to find
their way to Want_Land where they will find no barrier.
This probably happens in economics a lot. This is when a small amount can control a much larger amount. In electronics, when one unit of charge in the base can control 100 units of charge from the emitter to the collector, that is called a current gain or "Beta" of 100.
Bipolar transistor works in the same way. There are in fact two different kinds of currencies in Silicon. The normal currency are electrons which are labeled N for having a negative change. There is also something like an electron IOU or bill_for_an_electron that can be passed around much like a lunch bill among friends. This "hole" or vacuum of an electron behaves like an electron with a positive charge and is labeled with a P. Simply replace N for $ and P for #, and you get an NPN transistor shown below.
Between_Land
Base
_______________________________________
|NNNNNNNNNNN ->N P P ->N N N N|
|NNNNNNNNNNN ->N P ->N |
|NNNNNNNNNNN ->N P P ->N N N N|
|NNNNNNNNNNN <-P P | |
|NNNNNNNNNNN ->N P P ->N N N N|
|NNNNNNNNNNN ->N P ->N |
|NNNNNNNNNNN ->N P P ->N N N N|
|____________|__________|_______________|
^
Emitter /_\ Collector
Surplus_Land | Want_Land
one P per sec
The barrier that exist in the economic model works the same way
for the transistor. Whenever Want_Land loses an electron across the
border into Between_Land, it creates a want or need. In the
electrical world this is a voltage field which attempts to hold
back any more electrons from leaving. Like wise, if an area
is in need of electrons, it will not be to happy to accept
any further bills for electrons (holes) from its neighbor. Electrically the
same voltage field thereby prevents all charge from crossing the border.
Base
_______________________________________
|PPPPPPPPPPP ->P N N ->P P P P|
|PPPPPPPPPPP ->P N ->P |
|PPPPPPPPPPP ->P N N ->P P P P|
|PPPPPPPPPPP <-N N | |
|PPPPPPPPPPP ->P N N ->P P P P|
|PPPPPPPPPPP ->P N ->P |
|PPPPPPPPPPP ->P N N ->P P P P|
|____________|__________|_______________|
^
Emitter /_\ Collector
|
1 N per sec
Reverse N for P and everything behaves the same. Now you have a
PNP transistor.
So whether your talking economics or electrons, a small amount
of currency at the right place can sometimes control a much larger
flow of currency. Whether it be $ or #, P or N, holes or electrons,
the question is whether the currency can flow. An if barriers
naturally exist to restrict the flow, is there a position of advantage
where very little can control what happens to a lot.
Don_Sauer_May_04
dsauersanjose@aol.com