Newnes Dictionary of Electronics

X

X amplifier Same as horizontal amplifier.

X-cut crystal A slice of quartz crystal cut at right angles to an X axis and parallel to the optic axis. A quartz crystal has the shape of a hexagonal prism and the electric axes (along which the piezo-electric effect is a maximum) pass through the centre and opposite corners of the hexagon as shown in Figure X.1. The line through O perpendicular to the plane of the paper is the optic axis of the crystal. The shaded area on the diagram represents an X cut. Such slices are used to control the frequency of oscillators, e.g. those used to generate the carrier frequency of radio transmitters, but a disadvantage is that the natural resonance frequency of the slice (determined by its thickness) is temperature ...