電學講義第1章1-1電學講義 Circuits Notes瞿大雄 教授 國臺灣大學電機工程學系 中華民國959月課號:90120100電學講義第1章1-21. class: Friday 9:10-12:10, Room 225 2. textbook: Circuits, A. B. Carlson, Brooks/Cole, 2000 3. scopes: basic concepts and analysis methods of linear DC and AC circuits in frequency and time domains 4. contents: Ch.1 Circuit variables and laws 1.4, 1.5 Ch.2 Properties of resistive circuits, 2.3-2.5 linear equations Ch.3 Applications of resistive circuits, 3.2, 3.3 Ch.4 Systematic analysis methods, 4.1-4.4 Ch.5 Energy storage and dynamic circuits, 5.3 Ch.6 AC circuits, 6.1-6.3 linear differential Ch.7 AC power and three-phase circuits, 7.1, 7.2 equations Ch.8 Transformers and mutual inductance (skip) (time domain) Ch.9 Transient response, 9.1-9.4General Information電學講義第1章Ch.10 Network functions and s-domain analysis (skip) Ch.11Frequency response and filters, 11.1, 11.2, 11.4 linear Ch.12 Fourier series analysis (skip)equations Ch.13Laplace transform analysis, 13.1-13.3(frequency Ch.14Two-port networks, 14.1-14.3domain) Ch.15 Stae-variable analysis (skip)1-3電學講義第1章5. total class hour: 51 hours 6. grades: 5 Quiz (Ch. 3, 5, 7, 9, 11) 60%, Final exam. 40% 7. office: room 541, or thcew.ee.ntu.edu.tw 8. Notes are available at http:/cc.ee.ntu.edu.tw/%7Ethc/ or comm.ntu.edu.tw/faculty.htm1-4電學講義第1章Chapter 1 Circuit variables and laws 1.1-1.3 (optional) definitions and units of current, voltage, and electrical power, Ohms law 1.4 Kirchhoffs laws node, supenode, loop, KVL and KCL, series and parallel connections 1.5 Elementary circuits analysis voltage source and current source connections, branch variable analysis1-5電學講義第1章1-61.1-1.3 Optional 1. Definitions (1) current: equivalent positive charge transfer rate unit: amp (A) direction: direction of equivalent positive charge transfer average current over :(2) voltage (potential difference): energy change per charge between two points unit: J/C, volt(V) +: higher potential, -: lower potential dttdqti)()(+=TttT avdttiTTqti00)(1)(dqdwv ootttT +電學講義第1章(3) electric power: energy transfer rate unit: watt (W) +: consume power, -: supply power (a) total energy: unit: 1Wh=3.6103J (b) battery capacity: unit: 1Ah=1C/s3600s=3600C 2. Sources (1) ideal voltage source: a two-terminal element to supply specified voltage (2) ideal current source: a two-terminal element to supply specified current vidtdq dqdw dttdwp=)(+=TttTdttpw00)(iTvwqT T=1-7Nonlinear elements電學講義第1章3. Ideal linear resistor: a two-terminal energy-consuming linear element described by Ohms law unit: ohm () (1) i-v curve in I and III quadrants: passive element (2) conductance: unit: siemens (S) (3) power dissipation (ohmic loss): (4) resistivity : conductivity: unit: m (5) lumped-parameter model: no dimension or lRiv =1RGRvRivip2 2=AlR= 1=1-8電學講義第1章1.4 Kirchhoffs laws Basics 1. node: a connection point of two or more circuit element 2. KCL: the algebraic sum of all currents into any node equals zero3. loop: any path that goes from node to node and returns to the starting node, passing only once through each node (CW direction) 4. KVL: the algebraic sum of all voltage drops around any loop equals zero0)(321=+=iiiinode0)(21=+=x loopABEAvvvv0)()(5431=+=x loopABDEAvvvvvv0)(23=+=vvvvy loopBCEB1-9電學講義第1章Discussion 1. KVL and KCL are circuit relations (linear equations), irrespective to the element type. 2. i-v is the relation (linear or nonlinear equation) of circuit element 3. circuit analysis: to solve v and i based on equations of KVL, KCL and element i-v relations 4. supernode: a closed region that contains two or more nodes and whose boundary intersects some connecting wires, each wire being intersected only onceSupernodes save effort when ixis no need to solve. 5. series connection: same current through each element parallel connection: same voltage across each element0)()(432 sup1=+=iiiiiernode1-10電學講義第1章6. Ex.1.7 to solve unknown values in the circuitsup4433141332324210 10.500.510010201.520121 6071019086BB ernodeBnodeCB nodeAnodeDCECE loopCEBCloopAEFAloopDAFDloopDiiimAiiimAiiiimAiiiimAv vvVvvvVvvvvVvvv=+= = = = = = = = = = =+ = =+ +402CBDvV= =1-11電學講義第1章1-121.5 Elementary circuit analysis Basics 1. Series circuit: voltage source with series-connected elements (voltage divider), analyze with KVL and Ohms law (voltage source with parallel-connected elements: same voltage)2. Parallel circuit: current source with parallel-connected elements (current divider), analyze with KCL and Ohms law (current source in series with element: same current)電學講義第1章1-13Discussion 1. Ex. 1.8 a passive element operated with vx=10V and ix=2.5A, design the circuit with a 12V voltage source or a 3Acurrent source=+=8 . 00105 . 212serloopserRRv=+=2005 . 2103parnodeparRRi2. Branch va