Abstract: There is disclosed a drive regulation and control circuit for a tuning fork resonator also adaptable to other electrical devices wherein an approximately sine wave signal from a motion sensor is applied to an instantaneous level detector which causes a variable width pulse signal to be on during that portion of the sine wave signal where the instantaneous level exceeds an adjustable reference level; a control signal is generated with a magnitude varying as a moving average of the width of the variable width pulses; the control signal causes the reduction of current to the tuning fork drive to cause reduction of motion amplitude. An optional feature provides rapid response by activating a motion braking signal having a duration approximately equal to the variable width pulse "on" period.

Abstract: There is disclosed a light modulating structure including an open-ended housing within which an electromagnetically driven tuning fork structure is supported. The tuning fork is of composite construction including two L-shaped cross section elements and is manufactured by a method which involves shaping the tines portions of the elements to a desired thickness in a single machining operation before the elements are separated and joined together symmetrically at the toe of the L to form a composite tuning fork.