ECE 2006

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ECE 2006

• CIRCUIT ANALYSIS
• University of Minnesota - Duluth
• Lecture 1

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Instructor Scott R.Norr, PE

• BSEE North Dakota State University 1986
• Registered Professional Engineer, MN 1994
• Minnesota Power 1986 to 1997
• ECE Dept. at UM Duluth - 1999 to Present

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Course Details

• Textbook Hayt, et. Al.,Engineering Circuit
  Analysis, 6th Edition, McGraw-Hill 2002
• Lab Place/Time Tuesdays MWAH 391
• Course Assessment
• Homework 15
• Labs 25
• Midterms 40
• Final 20

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TOPICS

• Fundamental Laws of Electricity
• Circuit Theory
• Analysis Methods
• Operational Amplifiers
• Energy Storage in Caps and Inductors
• Transient Circuits
• AC Circuits

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A Crude History of Electricity

• 600 BC Ancient Greeks rub amber on cat fur to
  produce static charge
• Circa 0 AD Persians in present-day Iraq
  invent the battery for unknown (probably
  medical) purposes
• 1720s Stephen Gray shows that static charges
  can be conducted from point to point

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History (Cont.)

• 1750s Benjamin Franklins One Fluid Theory of
  Electricity unifies scientific approaches to
  electricity and forms the foundation of modern
  electrical theory
• 1800s Alessandro Volta makes his Voltaic Pile
  using zinc and copper disks submersed in an
  electrolytic solution (acid), thus re-inventing
  the battery, 1800 years after the Persians

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History (Cont.)

• 1820s Hans Oerstad discovers electromagnetism
  with his famous compass and current-
  carrying wire experiments
• Andre-Marie Ampere defines electric current and
  electromagnetism, invents the ammeter
• Georg Ohm delivers his theory of electricity,
  including what later became Ohms Law
• 1830s Michael Faraday enters the game
  and things get intense

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Physics of Electricity

• Charge (q) fundamental property of atomic
  structures measured in Coulombs
• One electron has a charge of -1.602 x10-19 C
• Electric Current (i) measures the rate of
  change in Charge unit is Amperes (C/s)
• Relationship
• i dq/dt

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Physics - Continued

• Voltage (v) The Electromotive Force (emf)
  required to move Charge around a circuit.
  Indicative of the Electric Field. Also called
  Potential Difference measured in Volts (J/C or
  N-m/C)
• Relationship to charge
• v dw/dq

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Physics Continued Some More

• Power (p) Rate of change in work (the expending
  of energy in time) measured in Watts (J/s)
• p dw/dt dw/dq dq/dt vi

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Electric Conventions

• Current Convention

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Electric Conventions (Cont.)

• Voltage Rise/Drop Convention

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Electric Conventions (Cont.)

• Source/Load Convention

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Fundamental Laws

• Ohms Law V IR
• Kirchoffs Laws
• Voltage Sum the voltages around a loop to
  Zero
• Current Sum the currents around a node to
  Zero
• Power Equation P VI

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Maximum Power Transfer

• Power Transfer is maximized when load impedance
  equals source impedance

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Laboratory Equipment

• Oscilloscope
• 1 M-Ohm Impedance
• Shunt Device
• Measures Voltages
• Always measure voltages with respect to scope
  ground

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Laboratory Equipment (Cont.)

• Multimeter
• Measures Voltage, Current, Resistance, etc.
• Shunt Device for Voltage (High Impedance)
• Series Device for Current (Low Impedance)
• Acts as a DC source when measuring Resistance
• NEVER measure resistance on an Energized Circuit

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SAFETY

• CONTACT WITH ELECTRIC CURRENT CAN CAUSE DEATH
• As little as 100 milliamperes (0.1 Amp) of
  electric current can kill, if it travels across
  the heart

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SAFETY (Cont.)

• Follow Instructions, Ask for Clarification
• Know where Safety Equipment is Located - Fire
  Extinguishers, Telephones, Fire Blankets, Eye
  Wash Stations, etc.
• Always Assume an Electric Circuit is Hot
  (Energized) and Dangerous and Act Accordingly

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SAFETY (Cont.)

• Keep Work Areas Clean and Uncluttered
• Double Check Circuit Wiring before Energizing
• Never Work Alone
• Wire with One Hand - Minimizes exposure to the
  Heart

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SAFETY CONCLUSIONS

• Always understand the Laboratory Procedures
  before touching anything.
• Always assume that electric circuits are
  potentially live and dangerous.
• Make sure there are adequate life saving
  resources available and know how to use them.

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Resistor Color Code