EE221 Quizzes

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EE221 Quizzes

• Spring 2005
• Instructor Dr. K.D. Donohue

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Quiz 1

• 1) (1 Point) What is a phasor?
• 2) (2 Points) Determine C in the circuit such
  that the phasor magnitude for vo will be zero.

vo _
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Quiz 2

• Use nodal analysis to find the phasor voltage
  for vo in the circuit below, given is(t)
  20cos(100t) A. Express Vo in terms of
  determinants derived from the nodal equations.

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Quiz 3
(2.5 points) Find the average power in each
element in the circuit below (including the
source). (0.5 points) Find the power factor of
the source (dont forget to indicate leading or
lagging).
j40 ?
-j50 ?
20 ?
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Quiz 4

• Vs denotes a 120-V rms 60-Hz source that
  supplies two loads connected in parallel, as
  shown below.
• a) (1 point) Find the power factor of the
  parallel combination.
• b) (2 points) Calculate the value of the
  capacitance connected in parallel that will raise
  the power factor to unity.

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Quiz 5

• a) (1.5 Points) Derive the transfer function
  and simplify to a rational polynomial of all
  non-negative powers of s (use sj?) for the
  circuit below where input is vi and output is vo
  (show your work).
• b) (1.5 Points) Sketch the magnitude and phase
  Bode plot for the transfer function below

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Quiz 6

• (2.5 points) for the circuit below with input
  i(t) and output v(t), determine the values for L
  and C so the circuit below will resonate at
  fo10kHz with a bandwidth B 1000 Hz.
• (0.5 points) Find the transfer function value at
  resonance and indicate the units.

v(t) _
C
L
100 ?
i(t)
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Quiz 7

• (2.0 points) Derive the Transfer Function for the
  circuit below with vi as input and vo as output
  (simplify so there are no negative powers of s in
  the rational polynomial).
• (1.0) Identify the filtering properties as either
  high-pass or low-pass and indicate the half-power
  cut-off frequency in Hz.

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Quiz 8 and 9 (Take Home)

• This is due Thursday March 24, 2005 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 work done to
  obtain the result should be clearly shown.
• A. For input vi(t) and output vo(t), derive the
  transfer function for the circuit below (3
  points). Show your work.
• B. Use Matlab to create Bode Plot for the
  transfer function in Part (A) (1.5 points). Hand
  in printouts of the graphs and code used to
  generate them. Graphs must be properly labeled.
• C. Simulate the circuit in SPICE and create a
  Bode plot (submit printout of SPICE schematic as
  well as the plots. Plot phase and magnitude
  separately) (1.5 points).

10 k?
10 k?
26.5 nF
26.5 nF
vo(t) -
8 k?
vi(t)
20 k?
10 k?
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Quiz 10

• Find the ABCD (Transmission) parameters for the
  circuit below

j2?
-j5?
-
-
4?
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Quiz 11

• Find the y (admittance) parameters for the
  2-port below

2?
1?
-
-
-
1?
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Quiz 12

• Find

j8?
-j20?
j4?
j7?
-
40?
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Quiz 13

• Find

20?
4?
1
-
-j3?
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Quiz 14

• A balance Y-connected load has a line voltage of
  and a phase impedance of
  20j6 ?.
• Find
• a) The phase voltage
• b) The line current