Basic Electricity

This side bar to our web page is, or was, supposed to be a place to teach our craft, explore new ideas, and pass along tips and techniques.  To some extant this has been the case.  But, mostly I have used it to vent on some of the incredibly stupid things people do, say, or try to push off on others.  I will try to do better in the future.


To that end, I am starting a short course in basic electricity — or — why you shouldn’t keep putting your finger in the wall socket.  I will try to keep my physics background in check while I do this, and deliver the message in a practical way that nearly everyone who is interested can follow.  For those of you who already know this stuff — move on, it is about to get boring.  For those of you who want to learn, and the few who do put their fingers in the wall socket — read on.


Starting with the most basic  point — What is electricity?


Electricity is the common name we have given to the flow of free electrons along a conductor.  The most prevalent conductor that we see on a daily basis (or at least the result) is copper wire.  Copper is a good carrier of electron flow because it gives up and replenishes its shell electrons easily.  Silver is slightly better at this.  Aluminum is also a very good conductor, but has other issues that make it less desirable as a widely used conductor.

The flow of the electrons is governed by a single and very simple rule called Ohms Law (E=IR).  We will get into the nuances of Mr. Ohm and his law down the road a ways.  For now look at the electrons moving along the wire as marbles rolling along a pipe.  If you lift one end of the pipe slightly, the marbles will roll faster.  If you tip the pipe so the outflow end is higher than the inflow end, the marbles will roll the other way.  If you put a valve in the pipe and close it slightly, or make the pipe smaller, the marbles will bunch up at the gate and slow down.  So — lifting one end of the pipe gives the marbles Potential Energy since they are moving from a higher plane to a lower one.  This is called Voltage, or Volts.  This higher potential energy is manifest as a faster marble flow, or Kinetic Energy, called Amperes, or Amps.  The frictional forces of the pipe or valve is Resistance, normally expressed as Ohm(s).


So E=IR is an expression that says Potential (E) is equal to current flow (I) times resistance (R).  Note how this is stated.  we do not say Volts equals Amps times Ohms since Volts, Amps and Ohms are units of measure not proper names.


If we have a resistance of one Ohm and pass a current of one Amp thru it — the potential is one Volt.  Easy-peasy.


The big thing about electricity is its ability to do work.  Work is expressed as Watts (W).  A potential of one Volt, flowing along a wire at one Amp, can do one Watt of work.  Seven hundred forty five of those Watts will equal one Horsepower of work done.

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