Fall 2000
Instructor: Dr. K.D. Donohue

Find the power absorbed or supplied by each network element in the circuit below.
+ 4 V -
1
I x
+
16 V
_
3 A
4 I x

Find the current I o in the circuit below.
3 mA 15k

-1 mA 10k

I o

Given I
L
= 4 mA, find V
S in the circuit below:
8k

I
L =
4 mA
2k

V
S
12k

4k


A) (2 points) Find V o by nodal analysis.
B) (2 points) Find I o by loop analysis.
9V
6

+
V o
-
6

2A
4

2

I o

Use Thevénin’s theorem to find I
0
Circuit below: in the
I o
6

9 V
2

12V 3


The voltage across a 10

F capacitor is given by: v c
( t )

0 V for t

0
5 ( 1
 exp(

10 t )) V for t

0 a) Find an expression for the current in the capacitor (3 points) b) Find an expression for the energy stored in the capacitor. (1 point)

This is due Tuesday October 10, 2000 at the beginning of the class period. Students must work independently on this assignment,
NO COLLABORATION. Any detected cheating will result in an E for the course for all involved parties. You are free to use any books, notes, or computer programs to solve this. If you get a result from a computer or calculator program (i.e. to solve a system of equations), indicate the program used to obtain the result. Otherwise all work done to obtain the result should be clearly shown.
A. Derive a set of equations that describe a complete set of node voltages or loop currents in the circuit below (2 points).
B. Use the set of equations to find V o
(0.5 points).
C. Simulate the circuit in SPICE and determine V o meter reading) (1.5 points).
(submit printout of SPICE schematic with
100

+ V x
-
50

I x
50

5 I x
1.5k

+ V o
-
20

4 V x
12V 40

10


v s
(
Determine equation for v o
( t ) for t > 0, when subjected to input pulse shown in figure.
Input voltage v s
( t )
6
5
4 t )
3k

6k

8k

.05mF
+ v o
( t )
-
3
2
1
0
-1 0 1 2 seconds
3 4 5

Find the equation for i ( t ), for t > 0
2 A t = 0
10
 t = 0
1
10
F 2

5
3
H i ( t )

This is due Tuesday October 31, 2000 at the beginning of the class period. Students must work independently on this assignment,
NO COLLABORATION. Any detected cheating will result in an E for the course for all involved parties. You are free to use any books, notes, or computer programs to solve this. If you get a result from a computer or calculator program (i.e. to solve a system of equations), indicate the program used to obtain the result. Otherwise all work done to obtain the result should be clearly shown.
(a) Use SPICE to plot v c
( t ) for t > 0. The time axis should be long enough to show voltage has reached an effective steady-state. (3 points)
(b) Find complete solution for v c
( t ) for t > 0 analytically. (1 point)
500

1k

5[ u ( t )u ( t -1)] V
0.01mF
+ v c
( t )
_
0.2H

i
Find the steady-state expression for i o s
( t ) = 10cos(100 t ) A
( t ) in the circuit below, if i s
0.5 mF 0.4 H i o
20


Find the phasor quantity for the circuit o below.
 j 12

10

0

V
8

I
ˆ x j 3

2 I
ˆ x

V
ˆ o


terms of phasors and impedances wrt terminals A and B ( note: the load has already been removed).
12

45

V
C
2

0

A j 8
 12
  j 12

B
C
Norton Equivalent Circuit
I
ˆ s
Z
ˆ
TH
B

This is due Tuesday Dec. 5, 2000 at the beginning of the class period. Students must work independently on this assignment, NO COLLABORATION. Any detected cheating will result in an E for the course for all involved parties.
Hand in a hard copy of the circuit and tables from SPICE that clearly show the requested results (can print directly from SPICE or paste into another program and print). Email the SPICE circuit file used in the simulation to donohue@engr.uky.edu
before 12/5/00 at 2pm. If you used a software package other than B2 SPICE, please indicate that in your email. Also make sure your name is somewhere on the email.
Use SPICE to find the phasors for the steady-state response of v o f o dB) and phase should be in degrees.
( t ), when
= 1, 10, 100, 225, and 1000 Hz. The magnitudes should be linear (i.e not in
0.1

F
5 k

1
2 cos

2
 f o t

V
5 k

0.1

F
20 k

5 k

+
v o
( t )