Why Take Electrical Engineering? Like computer literacy, electrical literacy is very important to engineering and everyday life So many things are powered or controlled by electricity It is used to communicate by video, wireless, phone or data So many physical phenomena are measured using transducers (devices that convert between a physical phenomena and an electrical voltage, current or resistance that is easily measured and recorded for analysis)

Some Transducers Light bulbs, buzzers, alerting devices Speed indicators Strain gauges pH sensors Temperature or light sensors Flow sensors Electric motors Sound or movement sensors

Problem Solving EE 188 also develops problem-solving and thinking skills – circuit problems must be solved using reasoning and thought, not just by plugging into formulas

Energy Crisis People are using up cheap, nonrenewable energy sources such as oil and coal Use of oil and coal produces excess carbon dioxide and global climate change 70% of oil is imported Dependent on global pricing variations Impacts our security

Renewable Alternatives Nuclear energy Atmospherically clean Dangerous Nuclear waste problems Wind energy Clean but unsightly Not dependable – needs storage capability Not abundant where needed most

Renewable Alternatives Solar More expensive Not dependable – needs storage capability Geothermal and Hydroelectric Environmentally sensitive Limited resources

Transportation Alternatives Plug-in electric gasoline hybrids Biofueled vehicles Natural gas-powered vehicles Hydrogen-powered vehicles Fuel cell-powered vehicles

Plug-In Electric Hybrids Potential Barriers?

Where Does Electricity Come From? We buy it from power plants We can generate it ourselves Diesel or gasoline generators Generated in our car Generated by home solar or wind power We can get it from batteries Sometimes we get it when we don’t want it Lightning Static

What is the main fuel used to generate electricity in the US?  Natural Gas  Oil  Hydroelectric  Nuclear  Coal  Wind, Solar, Biomass and Geothermal Put a one by the fuel most used, a 2 by the next most used, etc.

Fuels Used to Generate Electricity #1 Coal is used to generate 49% of the electricity in the U.S.

Fuels Used to Generate Electricity #2 Natural gas is used to generate 20% of the electricity in the U.S. http://www.power-technology.com/projects/bethlehem/index.html#bethlehem2

Fuels Used to Generate Electricity #3 Nuclear is used to generate 19.4% of the electricity in the U.S. http://www.srpnet.com/about/stations/paloverde.aspx

Fuels Used to Generate Electricity #4 Hydroelectric is used to generate 7% of the electricity in the U.S. http://www.desertusa.com/gc/gcd/du_glencandamtour.html

Fuels Used to Generate Electricity #5 Other Renewables account for 2.4% Wind Solar Biomass Geothermal

Wind Power

Solar Photovoltaics http://www.aps.com/my_community/Solar/Solar_22.html

Solar Parabolic Trough A trough can focus the sun at 30 to 100 times its normal intensity to heat liquid in the receiver pipe to over 400 degrees Celsius.

Solar Dish and Engine A solar dish concentrates the sun at a factor of 2000 achieving temperatures of 750 C to run an engine which turns a generator.

Fuels Used to Generate Electricity #6 Petroleum is used to generate 1.6% of the electricity in the U.S. http://www.power-technology.com/projects/riyadh/index.html#riyadh1

Fuel Usage Pie Chart (2006)

Energy Usage

Electricity Cost Chart (2006)

How does Electricity Get to Us? Wires connect the power plants to the users via the power grid. Long distances are covered by wires carrying hundreds of thousands of volts Same power delivered by half the current and twice the voltage Saves money on wire (typically 40mm in diameter) Saves money on losses due to resistance in the wire

Power Grid

Industrial Power Industrial plants use three phase power (480v) to run most large machinery They run small machines, lights, computers on single phase power (120/240v)

Residential and Commercial Residential and commercial customers use single phase power – 120 volts for most uses or 240 volts for high power appliances Transformers are used to reduce the high voltages on the power lines to the lower voltages needed

AC and DC Power Most power generated is Alternating Current (AC) power where the current and voltage varies sinusoidally with time Direct Current (DC) power doesn’t vary with time Most consumer products use both AC and DC http://www.pbs.org/wgbh/amex/edison/sfeature/acdc.html

DC Power DC power is used to power electronics DC power is easier to store (batteries) DC power is used in mobile applications DC power is useful when off the power grid Inverters convert DC to AC

AC Power AC power is easier to distribute Higher voltage and smaller current yields same power distributed Transformers make it easy to change voltage levels so smaller wire can used AC is used for most machinery, lights and appliances Power supplies convert AC to DC

Study of Circuits at NAU EE 188 – DC circuits and AC circuits when at steady state EE 280 – Transients, frequency response & both digital and analog electronic circuits EE 380 – Linear and nonlinear electronic circuits, device models and simulation EE 480 – Advanced Electronics EE 482 – Intro. to VLSI electronics design