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SECTION 6.8 Open and Short Circuits
30. For the network of Fig. 6.96:
a. Determine Is and VL. b. Determine Is if RL is shorted out.
c. Determine VL if RL is replaced by an open circuit.
31. For the network of Fig. 6.97:
a. Determine the open-circuit voltage V L.
b. If the 2.2-k� resistor is short circuited, what is the
new value of V L?
c. Determine V L if the 4.7-k� resistor is replaced by an
open circuit.
*32. For the network of Fig. 6.98, determine
a. the short-circuit currents I 1 and I 2.
b. the voltages V 1 and V 2.
c. the source current I s.
SECTION 6.9 Voltmeters: Loading Effect
33. For the network of Fig. 6.99:
a. Determine the voltage V2. b. Determine the reading of a DMM having an internal
resistance of 11 M� when used to measure V2. c. Repeat part (b) with a VOM having an ohm/volt rating
of 20,000 using the 10-V scale. Compare the
results of parts (b) and (c). Explain any difference.
d. Repeat part (c) with R1 � 100 k� and R2 � 200 k�.
e. Based on the above, can you make any general conclusions
about the use of a voltmeter?
SECTION 6.10 Troubleshooting Techniques
34. Based on the measurements of Fig. 6.100, determine
whether the network is operating correctly. If not, try to
determine why.
E
I 1
I s
100 �
FIG. 6.96
Problem 30.
PROBLEMS ⏐⏐⏐ 211
E 12 V
RL 10 k� VL 6 �
2.2 k� 3.3 k�
9 V 4.7 k� VL +
V1 –
FIG. 6.97
Problem 31.
4 �
FIG. 6.98
Problem 32.
I s
20 V
I 2
10 �
5 �
6 V R2 20 k� V2 3.5 mA
I
6 V 6 k�
10 k�
R 1
FIG. 6.99
Problems 33 and 40.
3 k� 4 k�
FIG. 6.100
Problem 34.
+
–
+
–
+
–
+
V 2
–
V 6 V