ECE 2006Instructor: Scott R.Norr, PECourse Details:TOPICSA Crude History of ElectricityHistory (Cont.)Slide 7Physics of ElectricityPhysics - ContinuedPhysics – Continued Some MoreElectric Conventions:Electric Conventions (Cont.)Slide 13Fundamental LawsMaximum Power TransferLaboratory EquipmentLaboratory Equipment (Cont.)SAFETYSAFETY (Cont.)Slide 20SAFETY CONCLUSIONSResistor Color CodeECE 2006CIRCUIT ANALYSISUniversity of Minnesota - DuluthLecture 1Instructor: 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 PresentCourse Details:•Textbook: Alexander/Sadiku – Fundamentals of Electric Circuits. 2nd Ed.•Lab Place/Time: Tuesdays – MWAH 391 •Course Assessment: •Homework: 15%•Labs: 25% •Midterms: 40% •Final: 20%TOPICS•Fundamental Laws of Electricity•Circuit Theory•Analysis Methods•Operational Amplifiers•Energy Storage in Caps and Inductors•Transient Circuits•AC CircuitsA 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•1720’s: Stephen Gray shows that static charges can be ‘conducted’ from point to pointHistory (Cont.)•1750’s: Benjamin Franklin’s One Fluid Theory of Electricity unifies scientific approaches to electricity and forms the foundation of modern electrical theory•1800’s: 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 PersiansHistory (Cont.)•1820’s: 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 Ohm’s Law•1830’s: Michael Faraday enters the game and things get intensePhysics 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/dtPhysics - 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/dqPhysics – 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 = viElectric Conventions:•Current Convention:Electric Conventions (Cont.)•Voltage Rise/Drop ConventionElectric Conventions (Cont.)•Source/Load ConventionFundamental Laws•Ohm’s Law: V = I*R•Kirchoff’s Laws:–Voltage: Sum the voltages around a loop to Zero–Current: Sum the currents around a node to Zero•Power Equation: P = V*IMaximum Power Transfer•Power Transfer is maximized when load impedance equals source impedanceLaboratory Equipment•Oscilloscope–1 M-Ohm Impedance–“Shunt” Device–Measures Voltages–Always measure voltages with respect to scope groundLaboratory 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 CircuitSAFETY•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 heartSAFETY (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 AccordinglySAFETY (Cont.)•Keep Work Areas Clean and Uncluttered •Double Check Circuit Wiring before Energizing •Never Work Alone •Wire with One Hand - Minimizes exposure to the HeartSAFETY 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.Resistor Color CodeBlk BR Red Or Yel Gr Blu Vi Gry Wht0 1 2 3 4 5 6 7 8 9First Band – “Tens” ColumnSecond Band – “Ones” ColumnThird Band – Power of 10Fourth Band – Tolerance:Gold = 5% , Silver = 10% Fifth Band – Ignore for nowIn this example: 10 x 102 =1000 Ohms +/-