EEE393 Basic Electrical Engineering
20 Feb 2007, Tuesday (bring to class)
HOMEWORK 2
1.
2. Find ejθ for θ=0, π/2, π, 3π/4, 2π. Show all on the unit circle in the complex plane.
3.
4.
5.
Unknown
Linear Circuit
a
b
When a 15k
Ω
resistor is connected between the
terminals a and b, Vab = 45V.
When a 5kΩ resistor is connected between the
terminals a and b, Vab = 25V.
Find the Thevenin equivalent of the unknown
circuit with respect to a, b.
(Hint: remember the line you draw in HW1, Q7.)
Vs=V0cos(
ω
t).
Find i.
+
V
S
R
L
i
I
S
R L
i
I
S
R C
i
Is=is a sinusoidal current source with angular frequency
ω
, in the form of I0cos(
ω
t).
Describe qualitatively how i, the current through R, changes as ω changes from 0 (DC) to infinity.
Use your knowledge of how the behavior of a capacitance and inductance change with frequency.
R
=2
Ω
L=1H
+
v
- C=0.05F +
vC
-
a) Find the complex impedance seen into the input
(left) port, as a function of ω. What is the
resistive part and what is the reactance?
b) Assume a complex input v and find the
(complex) ratio vC/v (a complex “transfer
function”). Plot the magnitude with respect to ω.
(Note: vC is also a complex signal, so we are not
doing any operation with real signals, or
conversion between real and complex signals).
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