2260
LAB 3 Oral Presentation Contents
Each student must make one oral presentation in lab during the semester.
Presentations will last five minutes and will be given at the beginning of the lab session. The
presentations will describe work performed the previous or current week in lab by way of
review. Practice your talk and be succinct. Stick to the five-minute time frame.
Week 2 of lab:
Presentation 3.1: Overview of x-y plots on oscilloscope
a) Explain that your presentation will discuss what types of figures you get on an
oscilloscope in x-y mode as a prelude to the patterns produced on the oscilloscope in
Lab 3.
b) Draw the following x(t) and y(t) waveforms versus time and then as they would appear
on an oscilloscope in x-y mode. (Explain why they produce the corresponding
patterns.)
i) x(t) = y(t) = sin(2!t)
ii) x(t) = sin(2!t), y(t) = cos(2!t)
iii) x(t) = square wave, y(t) = x(t) but shifted by one-quarter cycle
iv) x(t) = triangle wave, y(t) = x(t) but shifted by one-quarter cycle
c) Summarize your results.
Presentation 3.2: Dual spiral plots on oscilloscope
a) Explain that your presentation will discuss the spiral patterns produced on the
oscilloscope in Lab 3.
b) Draw the following x(t) and y(t) waveforms versus time and then as they would appear
on an oscilloscope in x-y mode. (Explain why they produce the corresponding
patterns.)
i) x(t) = sin(2!t), y(t) = cos(2!t) [to connect with previous talk]
ii) x(t) =
€
ae−
α
tsin(
β
t)
, y(t) =
€
be−
α
tcos(
β
t)
iii) x(t) =
€
ae−
α
tsin(
β
t)
, y(t) =
€
be−
α
tcos(
β
t)+c
iv) x(t) and y(t) as in (iii) until spiral dies out, followed by
x(t) =
€
−ae−
α
tsin(
β
t)
, y(t) =
€
−be−
α
tcos(
β
t)−c
(i.e., negative of previous x and y)
c) Summarize your results and point out that (iv) is what we get in Lab 3.
