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HERE COMES THE SUN A STUDY OF ELECTRICITY AND PHOTOVOLTAICS Institute Of Electrical And Electronic Engineers, Phoenix Section Teacher In Service Program / Engineers In The Classroom (TISP/EIC) Helping Students Transfer What Is Learned In The Classroom To The World Beyond

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Copyright Notice This presentation includes material copied from the web sites: HowStuffWorks How Solar Cells Work, http://http://science.howstuffworks.com/environmental/energy/solar-cell.htm (Copyright 1998-2010 HowStuffWorks, Inc.) Explain that stuff! Solar Cells http://www.explainthatstuff.com/solarcells.html Wikipedia, http://en.wikipedia.org/wiki/Solar_cell The Sun, http://imagine.gsfc.nasa.gov/docs/science/know_l1/sun.html Tennessee Valley Authority, Coal-Fired Power Plant, http://www.tva.gov/power/coalart.htm The Electricity Book, http://www.bgfl.org/bgfl/custom/resources_ftp/client_ftp/ks2/science/electricity_boo k1/index.htm and Here Comes The Sun from the Abbey Road album, 1969, by the Beatles This presentation may only be used free of charge and only for educational purposes, and may not be sold or otherwise used for commercial purposes http://http://science.howstuffworks.com/environmental/energy/solar-cell.htm http://www.explainthatstuff.com/solarcells.htmlhttp://en.wikipedia.org/wiki/Solar_cellhttp://imagine.gsfc.nasa.gov/docs/science/know_l1/sun.html http://www.tva.gov/power/coalart.htm http://www.bgfl.org/bgfl/custom/resources_ftp/client_ftp/ks2/science/electricity_boo k1/index.htm IEEE ASL 2 May 2012

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Comments on Solar Cars A solar car is an electric car powered from solar panels on the surface (generally, the roof) of the vehicle Solar vehicles are not practical day-to-day transportation devices at present, but are primarily demonstration vehicles. 3 May 2012 IEEE ASL

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The Solar Model Car You Will Build 4May 2012IEEE ASL Solar panels Rear Wheel Axle with Gear Assembly Motor Front Wheel Axle Assembly Cardboard Chassis

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What is the Sun??? May 2012 5 IEEE ASL

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What Is The Sun? 10,000F Surface 27,000,000 F Center 1,300,000 Earths May 20126 IEEE ASL The Sun is the STAR at the center of our Solar System The Sun has a diameter of about 1,392,000 kilometers (865,000 mi). By itself accounts for about 99.86% of the Solar System's mass

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Solar Energy From 400 Million Years Ago Coal, petroleum and natural gas formed from buried plant life They are carbon-based fossil fuels These are often referred to as "buried sunshine The sunlight is transformed through photosynthesis How do we convert this energy into useful work? SunlightPhotosynthesisPlant Life Cycle Heat, Pressure & TimeCarbon Based Compounds May 20127 IEEE ASL

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Coal (Or Gas Or Oil) Fired Electric Power Plant 8 May 2012 IEEE ASL

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What Are The Two Main Properties Of The Sun? AC OUT 2. Light 1. Heat Solar Thermal Power Arrays generate steam to drive Turbine Solar Cell Power Arrays generate electricity directly No Turbines/Generators! May 20129 IEEE ASL

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What Are Some Uses Of Electricity? 10 May 2012IEEE ASL Lighting Air conditioning Cooking Ironing Electric Motors Toasters Television Computers iPods Cell Phones Electric Guitars Welding Electric drill Table saw And on and on and on. In fact, life as you know it today would be completely impossible without electricity!

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Types of Electricity 11IEEE ASLMay 2012 Alternating Current - AC Direct Current - DC Dry CellsSolar CellsWet Cells Batteries

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Direct Current Sources 12 IEEE ASL May 2012 Batteries produce Direct Current (DC) like solar cells. Batteries create electricity by an electrochemical action. Solar cells create electricity by exposure to light.

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But What Is Electricity And What Are Its Properties? Deuterium Atom Copper Atom Electricity is the result of electrons moving in a uniform direction in material. This occurs best when the material is made up of atoms with free outer electrons IEEE ASL May 201213

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14May 2012IEEE ASL The movement of free electrons forms an electric current An Electric Circuit is formed by a Conductor to allow for the continuous movement of free electrons

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What Is A Solar Cell? 15 Solar Cell Symbol May 2012IEEE ASL A Solar Cell is also known as a Photovoltaic (PV) Cell It converts the energy of sunlight directly into electricity Photovoltaic combination of 2 Greek words Photo Light Voltaic Electric or Voltage

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What Makes A Solar Cell? A solar cell is a sandwich of two different layers of silicon material. The lower layer is p-type The upper layer n-type Then metal layers are placed on top and bottom. 16 IEEE ASL May 2012

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How Do Solar Cells Work? 17 IEEE ASL May 2012 2 1 5 1.When sunlight shines on the cell, photons (light particles) bombard the upper surface. 2.The photons carry their energy down through the cell. 3.The photons give up their energy to electrons in the lower, p-type layer. 4.The electrons use this energy to jump across the barrier into the upper, n-type layer and escape out into the circuit. 5.Flowing around the circuit, the electrons make the lamp light up. 3 4

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18May 2012 IEEE ASL

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Electrical Nature of Matter 19IEEE ASLMay 2012 Materials that permit the motion of free electrons are called Conductors. CONDUCTORS Silver Copper Gold Aluminum Brass Zinc Iron INSULATORS Dry Air Glass Mica Rubber Asbestos Bakelite PVC Teflon Plastics Materials that oppose the motion of electrons are called Insulators Conductors are said to have low resistance while insulators have high resistance

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Non Connected Electrical Circuit 20 IEEE ASL May 2012

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Connected Electrical Circuit 21 IEEE ASL May 2012

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Some Electrical Terms 22 IEEE ASL May 2012 V IR P VI Voltage (volts, V) V Amperes (amps, A) I Resistance (ohms, ) R Power (watts, W) P

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OHMs LAW I = V R P = V I V (voltage) R resistance May 2012 IEEE ASL 23

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May 2012 IEEE ASL 24

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How to connect circuits Series Circuit Parallel Circuit May 2012 IEEE ASL 25

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How to connect circuits Series Circuit Parallel Circuit May 2012 IEEE ASL 26

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How to connect circuits Series Circuit Parallel Circuit May 2012 IEEE ASL 27

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We Can Connect Batteries In Series And / Or Parallel 28 1.5V 3 W light bulb 1.0A 1.5V 3.0V Series Circuit 3.0V 3 W light bulb 0.5A 1.0A Series - Parallel Circuit Power = Voltage Current May 2012IEEE ASL P VI

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Gear Drive Solar Model Car 29May 2012IEEE ASL

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Applying the Series/Parallel Concept to the Solar Car 30 Series Circuit Parallel Circuit Power = Voltage Current 1.0V 1.5A 0.5V 3.0A 1.5A May 2012 IEEE ASL

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Lets Build Some Solar Powered Cars! May 2012 31 IEEE ASL

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Elements of The Solar Model Car 32May 2012IEEE ASL Solar panels Rear Wheel Axle with Gear Assembly Motor Front Wheel Axle Assembly Chassis

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Lets Build Some Solar Powered Cars! 1.Use foam board or corrugated plastic for the chassis 2. Make sure the axles are wider than the chassis 3.Assemble the wheels and gears on the axles with the axles through straws (use washers between the end of the straw and the wheels / gear) 4.Cut the straw length the same as the gap between the wheels to prevent the wheels binding on the chassis, but leave a little slack between the wheels 5.Tape the straws firmly to the chassis; for rear axle needs to be on top of the chassis, NOT underneath the chassis, or the gears will not mesh properly 6.Make sure the axles are parallel 7.Clip the motor to the chassis on top of the chassis, NOT underneath the chassis (it will rub on the ground otherwise) and align the gears so they mesh, but not too tightly 8.Assemble the solar panel (directions on the following charts) 9.Assemble a tilted platform for the solar array; note the direction to the sun! 10.Fit the solar array on the platform and connect the wires from the motor to the array connection pads with clips, red to + and black to 11.Handle the solar panels gently; they are fragile! DONT bend or cut them! 12.Keep the car as light weight as possible 13.Reverse the wires if the car runs backwards 33 May 2012 IEEE ASL

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Assembling Solar Cells Into A Panel Solar panels are made by gluing solar cells onto an insulating sheet and connecting them electrically in series The voltages add but the current is equal to that of a single cell For our solar car project we are providing two panels, each with three cells in series The current capability of a single cell is 1.5A and the voltage is 0.5V So for the three cell panel the current capability if 1.5A and the voltage is 1.5V 34 IEEE ASL May 2012

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Connecting The Panel To A Motor The electric motor you will be using for the solar cars requires 1.5 3.0V and 2.1 2.2A in order to start to run from stop If you connected two panels in series you would generate 3.0V and 1.5A If you connected them in parallel you would generate 1.5V and 3.0A Electric motors require current rather than voltage to start from stop so the parallel connection is recommended in this case 35 IEEE ASL May 2012

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Panels Connected In Parallel 36 May 2012IEEE ASL Aluminum Foil used here

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Solar Car Solar Array Assembly Process 37 May 2012IEEE ASL

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Step #1: Add Positive (+) Aluminum Foil Strip To Panel #1 38 May 2012IEEE ASL

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Step #2: Add Negative (-) Aluminum Strip To Panel #2 39 May 2012IEEE ASL

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Step #3: Final Assembly 40 May 2012IEEE ASL

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Elements of The Solar Model Car 41May 2012IEEE ASL Solar panels Rear Wheel Axle with Gear Assembly Motor Front Wheel Axle Assembly Cardboard Chassis

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May 2012 IEEE ASL 42

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Residential Solar System 43 IEEE ASL May 2012 Video of residential Solar System

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Solar Demo Circuit 400 watt, dc/ac inverter 110v ac A A A A V V Battery Charge Controller Solar Panels May 2012 IEEE ASL 44