13.10.2012 Views

boylistad

boylistad

boylistad

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

1184 ⏐⏐⏐ SYSTEM ANALYSIS: AN INTRODUCTION<br />

has the arrow in the symbol. Everything else in the network remains the<br />

same, so there is no need to rebuild the entire network. Simply make<br />

the changes and run the simulation. Even the simulation does not have<br />

to be changed since the chosen parameters will remain the same. The<br />

current source was given a magnitude of 1 A so that the magnitude of<br />

the VPRINT1 voltage would also be the magnitude of the output<br />

impedance. The results of Fig. 26.58 indicate an output impedance of<br />

200 k�. The following theoretical analysis reveals that the output<br />

impedance is indeed 200 k�:<br />

Zo � �<br />

1<br />

1<br />

���� ����6 �200 k�<br />

25 � 10 5 � 10 S<br />

�6 S � 20 � 10 �6 1<br />

————<br />

25 � 10<br />

S<br />

�6 (4 � 10<br />

S ��<br />

1 k�<br />

�<br />

1<br />

——<br />

4 h<br />

h<br />

)( 50)<br />

o � �<br />

rhf � �<br />

hi � Rs � 0<br />

FIG. 26.58<br />

Output file for the voltage across the 1-A current source (and output<br />

impedance) of the network of Fig. 26.57.<br />

PROBLEMS<br />

SECTION 26.2 The Impedance Parameters Z i and Z o<br />

1. Given the indicated voltage levels of Fig. 26.59, determine<br />

the magnitude of the input impedance Z i.<br />

E g<br />

+<br />

–<br />

1.05 V<br />

R s<br />

47 �<br />

+<br />

E i = 1 V<br />

Z i<br />

–<br />

FIG. 26.59<br />

Problem 1.<br />

System

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!