Electricity  

Nature of  Electricity

1. What is Electricity?  seeNDT  The movement of electrons- Free electrons   Franklin

2.   Making Electricity      Batteries need 2 different electodes and an electrolyte  Volta

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ZnCCellsParallelLabeled.jpg ZnCCellsSeriesLabeled.jpg ElectrolyteTraySetUpLabeled.jpg
Different electrolytes make better batteries
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Series mounted batteries to boost voltage - Much research today on batteries
Ranks wired in parallel to increase current flow and life

2.  3 Qualities of electricity:      Flow, Force, Resistance       Current,   Voltage,  Resistance  How We measure Electricity

Circuits  

3.  Pathways for electrons. Electrons flow from - to +

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4.  Series & Parallel       The two ways to arrange circuits

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batteries-series-parallel.jpg
SYMBOLID.jpg    symbolprobs2.jpg

5.  Conductors & Insulators        Insulators hold on to their electron more tightly           

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Conductors, Insulators, semiconductors and superconductors

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Ohms Law

6.   V=C*R    Voltage = Current x Resistance        volts = amps x ohms

OhmsLawexampleNumbers.JPG Numerical Demo of Ohm's law
Ohm's Law determines the result of changing voltage, current, or resistanc

Do Problems to understand     Example:   120 V = 4 A  x  30 Ohms

120 V = 12A  x  ___Ohms      ____V =  3 Amps  x  5 Ohms Two problems to try out     ProblemSet    Another Problem Set
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Magnetic Fields  

7.  An electric current creates a surrounding magnetic field                Oersted

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Research in Magnets
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8.  Induction:  An electric current in one wire creates an electric current in any neighboring wire.     Faraday

Current is produced in a conductor when it is moved through a magnetic field because the magnetic lines of force are applying a force on the free electrons in the conductor and causing them to move. inductance.gif    Induction Animation


 Induction Animation
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 Faraday Cages    EMP   Spying

Transformers

9.  An changing electric current in one coil of wire  creates an electric current in an adjacent coil. The relative number of loops in each coil determines the current and voltage in the 2nd coil.        Twice the loops - twice the voltage

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 TransformerVoltageA.JPG DSCFD887.JPG
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Also       Power in = Power out       or      A*V = A*V        So the  Ratio of the loops  increases one & decreases the other

Solenoids aka relays

10.  How Relays Work           Doorbells etc                Just Doorbells

A relay is an electrical switch that opens and closes under the control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835. Because a relay is able to control an output circuit of higher power than the input circuit, it can be considered to be, in a broad sense, a form of an electrical amplifier.

How a Relay Works 

Buzzer        Chime

Electric Motors 

 11.  A fixed magnet pulls on one that can move - a motor!

motor-labels.gif motor-parts.jpgHow Electric Motors Work - Eureka!
Motor

Build an electric motor and an electromagnet  --->
motor_running.jpg  Left: A simplified diagram of the parts in an electric motor.  Right: How it works in practice. Note how the commutator reverses the current each time the coil turns halfway. This means the force on each side of the coil is always pushing in the same direction, which keeps the coil rotating clockwise.

Generators

Generator Principle:  "A wire cutting through a magnetic field makes Electricity" 

Generator - Principle Of Operation, Alternating Current (ac) Generators, Commercial Generators, Direct Current (dc) science2969.jpg
Generators
YouTubeVideo of  Electromagnetic Induction creating Electricity
InductionDemoCamdenSchools.JPG

 Crash Course in Wind Turbines 

alternator.jpg Generator Principle Applet.Generates voltage AC or DC as a model

Power 

   Power is how fast energy is used                   Watts = Amps x Volts  

 

The Grid

 

Electricity is transmitted from its generation source to where we use it.  This path is called the Electric grid.


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Sound

  Electrical Energy is "Transduced" into sound


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 Excellent Sources of Science Info:NDTCourseOutline.JPGRonKurtisScienceSite.gif

 tiny links until permission granted: