【电路英文版课件】Circuitmodels-模型.pptVIP

2. Network variables (网络变量) The systems of units (M.K.S.system) (单位制) Length [meter] (m) Mass [kilogram] (kg) Time [second] (s) (4) Power--p(t) (W, k W, m W) * §1-1 Introduction The voltage source The current source The resistor The inductor The capacitor 1 Circuit models（模型） Two active（有源）models Three passive(无源）models current controlled voltage source Voltage controlled current source current controlled current source (CCVS) (VCCS) (CCCS) Voltage controlled voltage source (VCVS) (1) Current--i(t), I ---- (A,mA,μA...) The net time-rate of transference (传递) of charge is referred to as the flow of current. (2) Energy (or work)--w(t) (J) (5) Flux linkages(磁通链)--- (weber-turn) The time rate of performing work is defined as power. (3) Voltage --- (kV, V, mV) The ratio of work to charge is given the name voltage. 7 3. Reference directions(参考方向) (1) Reference directions for current (2) Reference directions for voltage 7 (3) Reference conventions (惯例) for two-terminal elements (R, L, C or ... ) The relative (关联) reference directions The reference arrow for the current variable enters the terminal, which is identified by the plus sign of the voltage reference polarity markings. *