AT – Cut Quartz crystal operating in Thickness Shear Mode (For QCM – Quartz Crystal Monitor Applications)
What is AT – Cut Quartz? AT – Cut Quartz means Y is the cut direction (thickness direction)and X is the wave propagation direction. In AT – Cut Quartz, the Y – axis is rotated by 35°21´ Therefore to obtain correct crystal orientation, one needs to get back to the definition of this crystal cut. AT – Cut Quartz is represented as yxl 35°21´ –which means “yx” is the initial position of the crystal, where the first letter “y” is the thickness direction the second letter “x” is the length direction. the third letter “l” indicates the axis of rotation (l = length). In this case, “x” is the axis of rotation. –For this configuration, the vibration mode is thickness-shear. Ref: John Buchanan, Handbook of Piezoelectric Crystals for Radio Equipment Designers, 1965.