Oscillations and
Waves >
Oscillations > Lissajous Figures
|
DCS# 1E20.17
|
STAR DISPLAY
-
APPARATUS
| oscilloscope |
214-01-E |
| differential amplifier |
101-02-C1 |
| two function generators |
214-01-D |
| two 500 - 6-8 Ω
matching transformers |
214-01-D |
DESCRIPTION
- This is a corridor display in
which
the user adjusts the frequency
of one of the two function generators to produce various
patterns on
the scope,
including a five-pointed star.
NOTES
- Adjust frequencies so that
each
function generator
produces a circular pattern by itself.
- Adjust amplitudes to
straighten the lines of the star. Do not exceed 4 VDC to
the differential
amplifier.
In
general, rational values of ω2/ω1 give (ω2 + ω1) -fold symmetry.
- For a five-pointed star: ω2/ω1
= 3/2 ⇒ 3 + 2 = 5 points.
REFERENCE
J. Gerard Anderson, “An
Electronic
Spirograph,” The Physics Teacher, February 1974, pp. 89-92.
