Electric Circuits, 9th Edition P72. Designed for use in a one or two-semester Introductory Circuit Analysis or Circuit Theory Course taught in Electrical or Computer Engineering Departments. Electric Circuits 9/e is the most widely used introductory circuits textbook of the past 25 years. As this book has evolved over the years to meet the changing learning styles of students, importantly, the underlying teaching approaches and philosophies remain unchanged. | 686 Two-Port Circuits Example Finding h Parameters from Measurements and Table Two sets of measurements are made on a two-port resistive circuit. The first set is made with port 2 open and the second set is made with port 2 short-circuited. The results are as follows The a parameters are n 77 Port 2 Open V 10 mV A 10 M F -40 V Port 2 Short-Circuited V 24 mV A 20 lA Z2 - 1 mA Find the h parameters of the circuit. Solution We can find zn and z21 directly from the shortcircuit test . v h 7 17 0 24 x 10 3 7 kil 20 x 10 6 20 X 10 6 The parameters hi2 and h22 cannot be obtained directly from the open-circuit test. However a check of Eqs. indicates that the four a parameters can be derived from the test data. Therefore hl2 and h22 can be obtained through the conversion table. Specifically 21 7 v2 . 12 - r rt22 2 0 10 x 10 3 -----77 -0-25 -40 10 x 10 6 - r- - - -25 x 10 3 x 10 6S 7 -24 ft IO 3 20 x HF6 _ ------- -20 x 10 3. IO 1 The numerical value of An is Ail fln 22 - 12 21 5 x nF6 - 6 x HF6 -HF6. Tli us An î 2 22 -IO 6 -20 x 10 3 x IO 5 _ 21 22 a22 x IO 6 -20 x 10 3 xS. assessment problem Objective 1 Be able to calculate any set of two-port parameters The following measurements were made on a two-port resistive circuit With port 1 open V2 15 V V 10 V and I2 30 A with port 1 short-circuited V2 10 V 12 4 A and 5 A. Calculate the z parameters. Answer 4 15 il Z12 1 3 n z2i -1-6 il Z22 0-5 il- NOTE Also try Chapter Problem . The Two-Port Parameters 687 Reciprocal Two-Port Circuits If a two-port circuit is reciprocal the following relationships exist among the port parameters 12 2b 1 12 2b it 1 22 12 21 11 22 12 21 12 2b 12 1- A two-port circuit is reciprocal if the interchange of an ideal voltage source at one port with an ideal ammeter at the other port produces the same ammeter reading. Consider for example the resistive circuit shown in Fig. . When a voltage source of 15 V is .
