Why Take Electrical Engineering?

1. 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 byvideo, 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)

2. 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

3. 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

4. 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

5. 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

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

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

8. Plug-In Electric Hybrids • Potential Barriers?

9. 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

10. 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.

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

12. 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

13. 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

14. 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

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

16. Wind Power

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

18. 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.

19. 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.

20. 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

21. Fuel Usage Pie Chart (2006)

22. Energy Usage

23. Electricity Cost Chart (2006)

24. 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

25. Power Grid

26. 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)

27. 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

28. 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

29. 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

30. 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

31. 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