email : kentaylo@swbell.net

Frequency divider for standing wave vibrators

Abstract

A simple electronic approach has been taken to modify the frequency of vibration of "standard" fixed-frequency vibrators used for generating standing waves on strings. These generators run off 60-Hz lines and generate standing waves haveing a frequency of 120 Hz. The frequency division is discrete.

• Support required for apparatus: 120-volt, 60 Hz outlet
• Approximate size: 5-6 ft long, 1 foot wide
• Does this apparatus require Electrical Power? yes
• Is this apparatus intended for use with an overhead projector? no
• Will you be present to set up your apparatus? yes
• When do you plan to set up your apparatus? Sunday, July 30 9-11 AM
• Other support needed for the proper operation of this apparatus: An instructional display will be provided for running the apparatus.

Sketch of the apparatus

(faxed in, maybe scanned later)

Description

A fixed-frequency vibrator (#1 in above sketch) which typically runs off a 120-V 60-Hz line is used for setting up a standing wave pattern in a string. Slotted weights (#4 in the sketch) suspended from a pulley (#3) create the required tension in the string (#2). The apparatus is modified from the stadard assembly by an electronic circuit which is housed in a box (#5) into which the vibrator power cord is plugged. The frequency modifier box is then plugged into the standard wall outlet. A switch provided on the modifier box allows one to select the desired frequency for driving the standing waves.