特勒根定理.ppt

文档介绍：Chapter 4
Circuit Theorems
电路定理
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Superposition Theorem 叠加定理
Substitution Theorem 替代定理
Thevenin-Norton Theorem
戴维南和诺顿定理
Tellegen Theorem 特勒根定理
Reciprocity Theorem 互易定理
Dual Principle 对偶原理
 Main Points:
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Linearity is the property of an element describing a linear relationship between cause and effect.
A linear circuit is one whose output is linearly ( or directly proportional) to its input.
§4-1 Linearity Property 线性
Homogeneity property 齐次性
Additivity property 可加性
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For Example Find I0
Solution: Assume: I0=1A , then
Homogeneity property 齐性定理
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The superposition Theorem states that voltage across (or current through) an element in a linear circuit is the algebraic sum of the voltages across (or currents through) that element due to each independent source acting alone.
§4-2 Superposition Theorem叠加定理
在任何含有多个独立源的线性电路中,每一支路的电压( 或电流) ,都可看成是各个独立电源单独作用时( 除该电源外,其他独立源为零电源)在该支路产生的电压(或电流)的代数和。
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j单独作用时
e单独作用时
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Steps to Apply Superposition Method:
Turn off all independent source except one source. Find the output(voltage or current) due to that active source using nodal or mesh analysis.
Repeat step 1 for each of the other independent sources.
Find the total contribution by adding algebraically all the contributions due to the independent sources.
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Example: Find v in the circuit.
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(1) The superposition principle is only applicable to a linear circuit . A linear circuit has homogeneity property齐次性 and additivity property可加性.
(2)独立源单独作用的含义是令其他独立源为零。
电压源短路
电流源开路
Note:
含受控源(线性)电路亦可用叠加定理,但受控源不能单独作用,受控源应始终保留。
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(5)The relationship p=Ri2 is nonlinear.
(4) The superposition principle can simplify circuit analysis。
功率不服从叠加定理!
(3)计算代数和时, 注意各分量前的“+”, “-”号。
当分量与总量的参考方向一致时,取“+”号;
与总量的参考方向相反时,则取“–”号。
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