- Reading:
In the Nilsson/Riedel text,
please study Chapter 9 (all sections) and review the topics from ELEC 225
(some review links are listed under Class Notes).
For Jan. 28 and the week of Feb. 1, please carefully study
Sections 9.10, 9.11, and 9.12 on transformers and phasor diagrams,
and review Sections 6.4 and 6.5 on mutual inductance.
Please read Chapter 14 on low-pass, high-pass, and band-pass filters,
and Chapter 15, Section 1 on Bode plots.
We covered much of this material in ELEC 225 and in
Lab 1,
and it may be helpful for answering item 7 below.
In Chapter 14, don't worry about the transfer function H(s).
The complex frequency response, H(jw), is defined as the ratio
of the output phasor to the input phasor.
Also, please review solving simultaneous linear equations and
complex number operations with your calculator.
- Please check your schedule of exams and projects
in other courses and compare with the tentative exam dates on the ELEC 226
syllabus.
Please let me know by Tuesday, Jan. 26 if the proposed dates are bad for you.
Feedback as of Jan. 26 favors exams on
March 2 and April 8. Let me know by Jan. 27 if you have a preference.
- See ELEC 226 on Blackboard for announcements about summer research opportunities.
-
We will have Lab 1 on Thursday, January 21 for all students.
-
Please review our work in ELEC 225 and identify topics or
particular problems that are difficult for you.
I strongly encourage you to meet with me this week
if you have any questions about material from ELEC 225 or
how to solve the problems on the ELEC 225 final exam.
The solution and histogram of scores for the ELEC 225 final exam
are posted on Blackboard (for ELEC 226) under Course Materials.
- Please bring your calculator to class on Tuesday, Jan. 26.
We will have a short quiz on complex number arithmetic and
solving simultaneous linear equations with complex coefficients.
- Please answer the following questions
and submit your solution in class on Thursday, Jan. 28.
These questions are very similar to analysis that we performed in
Lab 1.
Draw a circuit with a
sinusoidal voltage source vs(t) = 1 cos( w t) (V),
a resistor (R), and a capacitor (C) in series.
Specify the output voltage vo(t) so that the circuit will
be a high-pass filter in the sinusoidal steady-state as
the radian frequency w of the source is varied.
- Find the expression for the complex frequency response H( jw ),
which is defined as the ratio of the output phasor to the input phasor.
- Find the expression for the magnitude of the
frequency response, |H( jw )|,
and the phase shift, /_ H( jw ).
- Make a rough plot of the amplitude gain |H( jw )|
versus w.
Do this as a Bode plot of amplitude gain (in dB) versus frequency using a logarithmic scale on the frequency axis.
- Make a rough plot of the phase response, /_ H( jw )
versus w,
again using a logarithmic scale on the frequency axis.
- Find an expression for the cutoff frequency wc
as a function of R and C.
Indicate the location of wc on your Bode plots
in the previous items.
The cutoff frequency is the value at which the magnitude
of the frequency response equals 1/sqrt(2) times the maximum gain
(or reduction by 3 dB on a Bode plot).
- Specify values for R and C that will produce a cutoff frequency
of 1000 Hz.
(Note that wc is in radians/sec, so you need to convert
to Hz!)
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As we discussed in class, most homework assignments for ELEC 226
will be due on Tuesdays.
Homework 2 is posted and contains problems from
Chapter 9 that are due on Tuesday, Feb. 2.
-
Two junior EE students are available for tutoring and/or homework help as follows:
Trang Tran in Dana 303 on Wednesdays 7:00-9:00 PM
Dave Pike in Dana 303 Thursdays 7:00-9:00 PM
They are available to help students in ELEC 120 and ELEC 226, so you may see students from ELEC 120 if you visit them.
Thank you.