Apparatus:

A function generator sine wave was amplified by a  Kepco BOP amplifier, that signal was sent to the coil, inducing standing waves in the rod.  The standing waves were double the frequency of the signal, because the core contracts twice for each cycle of the signal.  A guitar pickup was used to pick up the motion, and its signal was sent to the lock in amplifier (LIA).  The LIA filtered out all but the 2f response of the rod, using the synch output signal of the signal generator as a reference.

Last Updated: 05/13/2008