BME 194 Winter 2013
Applied Circuits for Engineers
Feedback on lab 1
19:35 PST 20 January 2013
Overall, I was fairly pleased with how well students did the lab
write-ups for the thermistor lab, despite the lab having been longer
and more difficult than I had anticipated. Grades ranged from B+
down to C+, plus a couple of "REDO"s.
Any student may redo any lab
write-up, but those who get a "REDO" must redo them.
Students who turned in a joint report may redo the write-ups
individually or together, but once an individual report has been
turned in, then joint reports are no longer possible.
When redoing a lab report, turn in the old, commented-on report
attached to the new one. Don't wait a long time before redoing reports.
Warning: I have higher expectations for late or redone reports, so
don't make only trivial changes and re-submit—your grade can
go down. Make substantive changes that significantly improve the
quality before resubmitting.
Here were some common problems in the lab write-ups:
- The word "derive" does not mean "take the derivative of"—the
corresponding verb is "differentiate". Similarly "derivation" is
not the same as "derivative".
- The formulas for the B-equation and the Steinhart-Hart equation
need citations, including URL and date accessed if they were taken
from a resource on the web.
- The formulas used needed to be included in the report—just
invoking their names is not enough.
- Screen shots of gnuplot windows don't work well in reports, and
some of them were completely unreadable. Try using a script like epsscript:
set terminal postscript eps color
with the command
gnuplot < epsscript > script-name.eps
set terminal pdf color
with the command
gnuplot < epsscript > script-name.pdf
to produce eps or pdf vector images that can be included in documents.
- Including the gnuplot scripts you used as an appendix to your
report is a good idea.
- Don't mix unrelated things on the same plot (like resistance
vs. temperature and voltage vs. temperature). The axis labels
should always correspond to the data and curves plotted.
- Since the goal was to make a recording thermometer, you should
have come up with the formulas and scripts necessary to plot
temperature as a function of time.
- If you cut and paste formulas from the web, you must provide a
citation right after the formula—anything less is plagiarism.
In general, it is a bad idea to cut and paste formulas unless they
are using exactly the same notation as you use in the rest of the
report. You are better off learning how to format formulas in
whatever document processor you use, rather than blindly copying
stuff in a different notation.
- Many students claimed that the spec sheet had a very wide range of
B values for the thermistor (3000K–3500k), but this was a misreading of the spec
sheet. The same spec sheet is used for many different thermistors,
but the part number encodes more detailed information about which
parts of the spec sheet are relevant for this particular thermistor.
Re-read the part of the 01-thermistor
lab handout that explains how to interpret the part number.
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