quiz-3-soln - 50 V. Thus the currents in these resistances...

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Thevenin Equivalent Circuit – Example We would like to determine the Thevenin equivalent circuit at the terminals a and b. To do so, we need to compute two of the following three: (1) open circuit voltage, (2) short circuit current, and (3) Thevenin resistance R Th directly. Determination of open circuit voltage v oc by inspection: Let us use G as the reference for node voltages. By inspection, the voltage at node b, namely v b = 50V. By voltage division rule, the voltage at node a, namely v a = 100 200+300 300 = 60V. Thus v oc = 10V with terminal a at a higher po- tential than terminal b. G a b 300Ω 200Ω 100Ω - + 100 V C - + 50 V Determination of short circuit current i sh by inspection: It is easy to observe that the voltage across 200Ω as well as across 300Ω equals
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Unformatted text preview: 50 V. Thus the currents in these resistances are as shown. Hence i sh = 1 4-1 6 = 1 12 A. The Thevenin resistance R Th is given by R Th = v oc i sh = 120 . i sh 1 4 A 1 6 A G a b 300 200 100-+ 100 V C-+ 50 V G a b 300 200 100 C Direct determination of R Th from the independent source-less network: The independent source-less network can be con-structed as shown on the left side. It can be retraced as shown on the right. Then, R Th equals the paral-lel combination of 200 and 300 resistances and thus it equals 120. a 200 300 100 C G C G b The Thevenin equivalent circuit is shown on the right.-+ 10 V 120 b a...
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This note was uploaded on 06/17/2011 for the course EE 10 taught by Professor Chang during the Spring '07 term at UCLA.

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