Daily Archives: March 24, 2011

Voltage = electron suck

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[Today’s run: rest day]

In order to be an authentic Ham Radio Guy I have over the years tried to learn more about electricity and electronics.

One of the features of that study that boggles my mind is the difference between actual current flow and assumed current flow.

Somewhere back in the mists of time somebody assumed that electricity flows from the positive terminal of a battery to the negative terminal.  Isn’t that what you would expect?  That red wire attached to the battery in your car is the positive terminal and the black wire is the negative.  So you would think that the electricity stuff is coming out of the battery on the red wire and going back in on the black wire.

No.  Electrons actually are negative charges.  The positive terminal of the battery has a positive voltage, which means that it has a need for more electrons.  It sucks electrons like a vacuum cleaner.  The higher the voltage the more it sucks.  The electrons actually come out of the negative  and go into the battery on the red, positive wire.

Now here is the mind boggling part.  The black wire just attaches to the engine block.  And, let’s pretend you have need for more current so put another battery into your car system.  You would attach all of the black wires to the engine block, even if the batteries are at different voltages  (some suck more than others).  So all of the batteries make this pool of available electrons and everything with voltage pulls in the number of electrons available in proportion to the amount it sucks.  And they call that common-connection-of-all-black-wires the “ground”.

Instead of thinking about electric circuits as a hose spurting electrons you really have to think of them like a vanilla milkshake full of electrons and someone sucking on a straw trying to get some milkshaky goodness.   Sucking is voltage.  Milkshake in the straw is current.  Small straw means harder to get much out of it: resistance.

And you look at some electrical schematic and it implies, “start here, go this way” and it is all such a lie!  The symbols for diodes and transistors even have little arrows… that point the wrong direction.  The names are right (emitter emits, collector collects) but the symbols are wrong.

I find vacuum tube circuits to be more transparent as far as depicting the actual current flow.  But that may be because I have a little better understanding about the way current moves through a tube than through a transistor.





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Mar 24, 2011
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