boylistad

16. Find the distance in millimeters between the plates of a
parallel plate capacitor if the maximum voltage that can
be applied across the capacitor is 1250 V. The dielectric
is mica. Assume a linear relationship between the breakdown
strength and the thickness of the dielectric.
SECTION 10.7 Transients in Capacitive Networks:
Charging Phase
17. For the circuit of Fig. 10.81:
a. Determine the time constant of the circuit.
b. Write the mathematical equation for the voltage vC following the closing of the switch.
c. Determine the voltage vC after one, three, and five
time constants.
d. Write the equations for the current iC and the voltage vR. e. Sketch the waveforms for vC and iC. 18. Repeat Problem 17 for R � 1 M�, and compare the
results.
19. For the circuit of Fig. 10.82:
a. Determine the time constant of the circuit.
b. Write the mathematical equation for the voltage vC following the closing of the switch.
c. Determine vC after one, three, and five time constants.
d. Write the equations for the current iC and the voltage vR. e. Sketch the waveforms for vC and iC. 20. For the circuit of Fig. 10.83:
a. Determine the time constant of the circuit.
b. Write the mathematical equation for the voltage vC following the closing of the switch.
c. Write the mathematical expression for the current iC following the closing of the switch.
d. Sketch the waveforms of vC and iC. SECTION 10.8 Discharge Phase
21. For the circuit of Fig. 10.84:
a. Determine the time constant of the circuit when the
switch is thrown into position 1.
b. Find the mathematical expression for the voltage
across the capacitor after the switch is thrown into
position 1.
c. Determine the mathematical expression for the current
following the closing of the switch (position 1).
d. Determine the voltage vC and the current iC if the
switch is thrown into position 2 at t � 100 ms.
e. Determine the mathematical expressions for the voltage
vC and the current iC if the switch is thrown into
position 3 at t � 200 ms.
f. Plot the waveforms of vC and iC for a period of time
extending from t � 0 to t � 300 ms.
R
100 k�
+ vR –
E 20 V C
FIG. 10.81
Problems 17 and 18.
E 100 V C
R2 50 V
R 1
2.2 k�
3.3 k�
– vR +
FIG. 10.82
Problem 19.
+15 V
(t = 0 s)
R 56 k�
iC C 0.1 µF µ
R 1
3 k�
–10 V
+
vC –
FIG. 10.83
Problem 20.
1
2 3
PROBLEMS ⏐⏐⏐ 427
i C
+
5 mF vC i C
+ vC –
C
2 mF
FIG. 10.84
Problems 21 and 22.
–
+
1 mF vC R 2
–
i C
2 k�