PURPOSE: To show stable Lissajous figures.

DESCRIPTION: Various harmonics from the Fourier synthesizer are input into the horizontal and vertical inputs of an oscilloscope, creating Lissajous figures. Any ratio of harmonic numbers can be used (including two first harmonics) with their phases and amplitudes independently adjustable.

SUGGESTIONS: You can get a neat effect by using the "dot" display style and a 2.50 second variable persistence. Change the phase of one of the inputs and watch the pattern change! Click your mouse on the photograph above to see it. Click here to see a different one.

See Question of the Week #221 for information on using this demonstration to enhance class involvement.

REFERENCES: (PIRA 3A80.20)

EQUIPMENT: Fourier synthesizer and oscilloscope.

SETUP TIME: 5 min.