ECE60L, Components & Circuits Laboratory (Spring 2003)
Farrokh Najmabadi


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NOTICES:

Final Scores and Course Grades are posted. You can pick up your final as well as your Lab reports from my assistant Phyllis Voigts in 460D EBUII (across the hall from my office).

Click here for the distribution of final scores and

Click here for Solution of the final.

Final: Average: 38/70 (3 students got 69/70)
Course Grade: Average: B- (10 A+)
Overall a good class, Most of the students have understood the concepts. I enjoyed having you in my class. Keep up the good work! Feel free to come and talk to me if I can be of any help

Observations on the Final:

General
1) Grades tremendously suffered because a lot of students do sloppy work: messy write-up leading to forgetting terms, decimals moving around, etc. Several students in this class broke the record in turning in the most "unreadable" finals. A large portion of the class would have got a better grade if they had not made sloppy mistakes in their final!
2) Many students still do not grasp that they are trying to be an engineer not a mathematician. Numbers are quoted as 1000pi (would you accept if the scope gives 1000pi in the lab?) or have many digits. One student had the record. In the first problem he quoted the center frequency as 88857.65875! Invariably these students made math mistakes carrying these extra digits around.
3) About half of the students still quote numbers without any UNITS. These numbers are meaningless.
4) A sizable minority still cannot do circuit analysis. Ladies & Gents, you should be able to write KVL and KCLs and be correct 99.9% of the time. You need to know this if you want to be a EE.

Problem 1. (Active band-pass filter) Majority of the class got this right. However, lots of students still confuse omega (rad/s) with f (Hz). A lot of students just did not write any units for omega and lost points.

Problem 2. (BJT NAND Gate) about 80% of class relabeled the BJTs to match v1 and v2. (I relabeled them also in the solution above to be conforming with most of the class).

A) Lots of students did not read the problem. Assume low voltage is zero instead of given 0.4 V. A few students even used 5 V as HIGH.
B) Lots of statements were made without any mathematical proof (similar to problem 5). These students lost a lot of points.
C) A large fraction of students claimed that the circuit is symmetric. It is NOT.
D) Lots of unnecessary work. In every case that one of the BJTs was off, you could find V0 regardless of the state of the other BJT. Many students went through and tried to find the state of other BJT.
E) Several students said that vCE=0 in the cut-off.

Problem 3. (OpAmp) Majority of students did this problem correctly.

Problem 4. (Active filter design). A good portion of the class did not say why they choose the circuit ( K > 1). Only two students in the class checked the OpAmp chip bandwidth!

Problem 5. (FET NAND gate). Most of students got this right.

Problem 6. (FET current mirror). Most bizarre solutions for parts A and B! A couple of lines of answer had turned into pages of math.

Problem 7. (BJT amplifier). Almost everyone got this right. Good Job.

The following two useful write-ups describe the fundamentals of Scopes and Probes.

XYZs of Oscilloscopes (Look under Resources/Application Notes/Primers)

XYZ of Probes (Look under Resources/Application Notes/Primers)

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