SUMMARY

Monday, 20 August 2018

1:30 PM

Machine generated alternative text: Topic 4 recap Superposition principle in linear circuits (circuit analysis). — The response of a linear circuit (a voltage or current of an element) with multiple sources is the algebraic sum of individual responses due to each independent source when the rest are turned off. Dependent sources are left intact during all calculations. • Source transformation (circuit analysis/simplification). Consists in replacing a voltage source vs (independent or dependent) in series with a resistor with a current source is (independent or dependent, respectively) in parallel with another resistor at the same terminal or vise versa. Vs or vs = Ris. • The transformed resistors are the same. • Thevenin's theorem. A linear circuit can be replaced (modelled) with a voltage source VTh in series with a resistor RTh from a given terminal. VTh is equal to the open-circuit voltage across the terminals (VTh = voc). RTh is obtained as: Ratio of the open-circuit voltage to the short-circuit current at the terminal pair. • Input resistance measured at the terminal pair when all independent sources are turned off (note that this method cannot be used for dependent sources).

 

Machine generated alternative text: • Norton's theorem. — A linear circuit can be replaced (modelled) with a current source IN in parallel with a resistor RN from a given terminal. IN is equal to the short-circuit current at the terminals (IN = is c). RN is the same as RTh. • Thevenin-Norton transformation is exactly the same as source transformation. VTh - RNIN or IN R Th RTh = RN = voc • Maximum power transfer If RL = RTh the power transferred to the load RL is maximum. 2 Pmax 4RTh 2

 

 

 

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