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Electrical Engineering Basics Around the Home Part II. UEET 101. Presented by Donald S. Zinger. Review Electricity Everywhere. Entertainment Communication Industry Lights Anything dealing with electron flow Electrical engineers involved in all. Electrical Engineering Major Areas .
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Electrical EngineeringBasics Around the HomePart II UEET 101 Presented by Donald S. Zinger
ReviewElectricity Everywhere • Entertainment • Communication • Industry • Lights • Anything dealing with electron flow • Electrical engineers involved in all
Electrical Engineering Major Areas • Signal and Systems • Communications • Controls • Digital • Computers • Logic Systems • Power • Generation and distribution • Power conversion
Quantifying Electricity • Current • Flow of positive electrical charge • Measured in Amperes • Voltage • “Pressure” that causes current to flow • Measured in volts • Impedance • Circuit opposition to current flow • Resistance in many circuits • Measured in ohms (W)
Basic Electrical Quantity Relationships I = current V = voltage Z = impedance (resistance for dc) P = power W = energy (work)
Example Calculations • Find P for various voltages • Z = 2 W
Design Process • Find a consumer need • Determine technical specifications • Develop system and components • Evaluate design • Repeat as necessary
Tools of Electrical Engineer • Calculator • Analysis and design • Computer • Analysis and design software • Simulation software • System (e.g. Simulink) • Circuit (e.g. PSPICE)
Example of PSPICE • Simple circuit • Battery and resistor • Highly complicated circuits possible
Other Tools Laboratory Equipment • Testing and evaluation • Meters • Measure average& RMS values • Oscilloscopes • Measure time varying values • Others • Signal generators • Spectrum analyzers • Etc.
Example:Electric Glove • Developing an electrically heated glove • Uses resistive heat • Nominal heat 1 W • Not to exceed 2 W • Should last 2 hours (90% of nominal power).
Challenge: Choose Resistance and Battery • Light weight • Meets original specifications
+ + Batteries in Series • Voltages add • Total energy increases Pictorial Schematic
+ + Batteries in Parallel • Current capability adds • Total energy increases • Current sharing problems Pictorial Schematic
Battery Choices From: http://www.duracell.com/oem/Pdf/others/alkaline.pdf
Class Problem • Divide into groups (4 to 5 people) • Decide on a set of batteries and a resistance • A number of designs will be randomly chosen and simulated • All designs meeting spec will be compared for weight • Lowest weight to meet specs will be “winner”
Discharge Curves From: http://www.duracell.com/oem/primary/alkaline/alkaline_manganese_data.asp D Cell C Cell AAA Cell AA Cell
What was done • Found a consumer need • Desire for warm hands • Determined technical specifications • Previously defined • Developed system and components • Found battery and resistance • Evaluate design • Simulated • Eliminated unsuitable designs
Should Repeat Cycle • Where specifications proper? • 1 W enough? • 2 Hrs long enough? • Would design work as expected? • Simulation model • Need to build to actually check? • Other factors • Glove materials • Reliability • Reproducibility
Math, Science, and Engineering Skills Needed • Emphasized in course work • Basis of all steps of design • Engineers should have a solid grasp of fundamentals
Technology always changing Computer processing power Other areas as well Need to keep active Technology Changes Graph from: http://www.awe.co.uk/main_site/scientific_and_technical/publications/discovery/pdf/discovery_july_2001/computers.pdf
Engineers Not Alone • Work in teams with others • Electrical • Industrial • Mechanical • Work with others • Marketing • Manufacturing • Look at big picture • Societal implications • Ethical Considerations
Summary • Electrical engineers involved in many designs • Design requires many interconnected steps • Based on fundamentals • Constantly improving • Keep the big picture • Team work • Society as a whole