Abstract: A display device for use in constructing remote controlling billboards, bus destination signs, and the like has a two-sided display disc which is carried on a pivoted support. The display disc is rotated by the application of force from a piezoelectric crystal drive to a point on the support which is off of the axis of rotation of the support. The crystal drive responds to DC voltage of one polarity or the other to rotate the display disc to expose a dark side or a light side to the viewer.

Abstract: A crystal vibrator actuated relay device including a switch having a contact button displaceable between first and second positions, the switch being open at one of the positions and closed at the other of the positions. A first lever arm is coupled to the contact button and is displaceable with the contact button between first and second positions corresponding to the first and second positions respectively of the contact button. A bias means as provided for biasing the contact button to the first position. A crystal vibrator is coupled through first and second coupling members to the first lever arm, the vibration of one of the coupling members causing one of the two coupling members to be displaced, to in turn displace the first lever arm to its second position to selectively control the switching of the switch.

Abstract: A timing device comprises a container of a transparent material, a channel in said container, and a flotation liquid and a float in said channel, said float having a density different from that of said flotation liquid. Flotation liquid compositions are disclosed which provide a transit time of said float through said channel which is essentially independent of temperature over the normal ambient room temperature range. A number of the embodiments provide for adjustment of the transit times over a substantial range of times.