Electrical Engineering ⇒ Topic : Nortons Theorem
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Samual
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NORTON'S THEOREM This theorem is the converse of Thevenin's theorem. It consists of an equivalent current source in parallel to the internal resistance of the network. This theorem states that Any two terminal linear active bilateral networks can be replaced by an equivalent current source in parallel to a resistance. The current source being the short circuited current through the load terminals and the resistance being the internal resistance of the source network looking through the open circuited load terminals. Explanation Firstly, consider a circuit shown in Figure 1 (a). We will determine the current through rL by using Norton's theorem. Let us apply the following procedures: (1) The load resistance rL is removed from the terminals A-B and the terminals A-B are short circuited [Figure 1 (b)]. FIGURE (1) (2) Now, let us determine ISC from Figure 1 (b). (3)To find out the internal resistance of the circuit, the short circuit across the terminals A-B is removed. The voltage source is replaced by short circuit as it has zero internal resistance. The circuit configuration is depicted in Figure 1 (c). From Figure 1 (c), we get (4) Next, the load resistance rL is connected across the terminals A-B. The circuit is represented in Figure 1 (d). The current IL through the load resistance rL is given by | |
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Mason
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Recall that Norton's theorem for d.c. circuits allows us to replace a two-terminal linear d.c. circuit by a single equivalent d.c. current source A two-terminal linear a.c. circuit can be replaced by a single equivalent a.c. current source FIGURE (A) Figure (a) shows the Norton equivalent circuit of a two-terminal a.c. circuit. The impedance | |
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William
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Norton's Theorem Norton's theorem is similar to Thevenin's theorem. While Thevenin's theorem is based on the idea of an equivalent source of emf, Norton's theorem is based on the idea of an equivalent current source. Norton's theorem can be stated as follows. Any arrangement of the sources of emf and the resistances can be replaced by an equivalent current source in parallel with a resistance r. The current from the source is the shortcircuit current in the original system and r is the equivalent resistance of the network between its two terminals A and B when all sources of emf are replaced by their internal resistances. Consider the network shown in Fig. (1). Let V' be the potential across AB when load resistance R is disconnected, as shown in Fig. (1) (a). Consider the load resistance R connected as shown in Fig. 1 (c). Then Now, the network shown in Fig. 1 (a) can be replaced by a current source driving a current I through the load R as shown in Fig. 1 (d). Then, we have figure (1) Circuit to illustrate Norton's theorem | |
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