Heavy-duty electric tuning fork. An electromagnet drives the fork to a sustained frequency of 80Hz. The tuning fork assembly and binding posts are mounted on a stable cast-metal base.To show relationships between frequency length tension and mass or learn about Melde’s standing wave experiments with this heavy duty electric tuning fork. An electromagnet drives the fork to a sustained frequency of approx. 80Hz. One prong of the tuning fork has a captive knurled thumbscrew for performing Melde’s experiment. Amplitude of the tuning fork vibrations is varied by means of a threaded adjustment screw. Universal binding posts are finished to provide electrical power from an external source of 2 to 6 volts DC.