Purpose:Demonstrate addition of two sine waves with variable phase difference.
Description:Two identical sine waves from the University of Maryland Fourier Synthesizer are added together and the sum is viewed along with each component using a three-trace oscilloscope. The sum can be studied as the phases of one or both of the component waves are varied.
This demonstration can be used as an aid in the study of beats or interference of sound waves. Invite students to make predictions about the effects of changing phase and amplitude of components.