电路原理课件讲义英文版Chapter7.pptVIP

I often say that you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of a science, whatever the matter may be.. ---Lord Kelvin Chapter 7First-order Circuits 7.1 Introduction 7.2 The Source-free RC Circuit 7.3 The Source-free RL Circuit 7.4 Singularity Functions 7.5 Step Response of an RC Circuit 7.6 Step Response of an RL Circuit 7.1 Introduction 7.2 The source-free RC circuit 7.3 The source-free RL circuit 7.4 Singularity Function (奇异函数) 7.5 Step Response of A RC Circuit 7.6 Step Response of A RL Circuit 7.9 Application 例2 t=0时 , 开关K由1→2，求电感电压和电流及开关两端电压v12。 解 iL K(t=0) + – 24V 6H 3? 4? 4? 6? + － vL 2? 1 2 t 0 i L + – vL R Singularity Function (switching functions) are functions that either are discontinuous or have discontinuous derivatives. Types of Singularity Function: unit step (单位阶跃); unit impulse (单位冲击); unit ramp (单位斜坡) Unit Step Function Usage of Step Function in circuit (Switching) Voltage source Current source Unit Impulse Function Usage of Unit Impulse Function Sampling (取样) or sifting (过滤) Unit Ramp Function Relationship of these three Functions Or The step response of a circuit is its behavior when the excitation is the step function, which may be a voltage or a current source. Applying KVL: In addition, So, For t0, then Thus, Complete Response (2) If V0=0 , there is Or, (1) If Vs V0 , then Systematic approach for finding the step response The natural response or transient response is the circuit’s temporary response that will die out with time. The forced response or steady-state response is the behavior of the circuit a long time after an external excitation is applied. Conclusion Three thin