Zero Temperature Coefficient Of Frequency Research Articles

Higher-Order Temperature Coefficients of the Elastic Stiffinesses and Compliances of Alpha-Quartz

The first-, second-, and third-order temperature coefficients of the elastic stiffnesses and compliances of alpha-quartz have been derived from thickness mode resonances of double-rotated quartz plates employing Christoffel's theory of wave propagation. The temperature dependence of all possible thickness modes can be calculated from the values of the elastic stiffnesses and their temperature coefficients as derived during this investigation. A curve showing the locus of the first-order zero temperature coefficient of frequency of thickness-shear modes has been calculated and compared with experiments. The second- and third-order temperature coefficients of frequency of the first-order zero quartz cuts are given. Applications to AT, BT, CT, and DT cuts are made by comparing the calculated with the experimental values which characterize the temperature behavior of frequencies and new useful piezoelectric cuts of quartz are indicated.

Determination of a few zero temperature coefficient (TC) cuts of Y-cut EDT crystals for longitudinal mode of vibration

The zero temperature coefficients of frequency for longitudinal mode of vibration for Y-cut crystals are studied with respect to their w/l (width to length ratio) for different ψ angle of cut. Zero TC cut for ψ=180° (i. e. length along the x axis) is studied in conjunction with coupling effect and the changing modes of vibration of the main longitudinal, first and second flexural and other strong modes. Further, the zero TC cut for ψ=160° and ψ=170° are studied and their corresponding w/l given.

Piezo-electric Resonator of Ethylene Diamine Tartrate with Zero Temperature Coefficient of Frequency

IF thin square plates of ethylene diamine tartrate have two sides parallel to the Y-axis, the axis of two-fold symmetry, so that the normal to the plate is in the XZ-plane, then there are two values of the angle θ between the normal and the X-axis which lead to zero temperature coefficient of the frequency of the contour shear mode. (The angle θ is measured from the positive direction of the X-axis towards the negative direction of the Z-axis.)

New Low-Coefficient Synthetic Piezoelectric Crystals for Use in Filters and Oscillators

Two crystals of the monoclinic sphenoidal class have been found which have modes of vibration with zero temperature coefficients of frequency, high electromechanical coupling constants, and high Q's or low dissipation. These properties make it appear probable that such crystals may have a considerable use in filters and oscillators as a substitute for quartz, which is difficult to obtain in large sizes. These crystals are ethylene diamine tartrate (EDT) having the chemical formula C 6 H 14 N 2 O 6 , and di-potassium tartrate (DKT) having the formula K 2 C 4 H 4 O 6 -1/2 H 2 O. The paper describes the properties of EDT, since this crystal has been found more advantageous than DKT. The 13 elastic constants, the 8 piezoelectric constants, and the 4 dielectric constants have been measured over a temperature range, and from these measurements the regions of low temperature coefficients and high electromechanical coupling have been located. Six low-temperature-coefficient cuts have been discovered and the properties of these cuts are given. These cuts are being applied in the crystal channel filters of the long-distance telephone system, and may be applied to the control of oscillators.

Properties of Monoclinic Crystals

Two crystals of the monoclinic sphenoidal class have been found which have modes of vibration with zero temperature coefficients of frequency, and this property together with the high electromechanical coupling and the high $Q'\mathrm{s}$ make it appear probable that these crystals may have considerable use as a substitute for quartz which is difficult to obtain in large sizes. These crystals are ethylene diamine tartrate ${(\mathrm{C}}_{6}$${\mathrm{H}}_{14}$${\mathrm{N}}_{2}$${\mathrm{O}}_{6}$) and dipotassium tartrate ${(\mathrm{K}}_{2}$${\mathrm{C}}_{4}$${\mathrm{H}}_{4}$${\mathrm{O}}_{6}$, \textonehalf{}${\mathrm{H}}_{2}$O). Complete measurements of the elastic, piezoelectric, and dielectric constants of the dipotassium tartrate (DKT) crystal are given in this paper. The crystal has 4 dielectric constants, 8 piezoelectric constants, and 13 elastic constants. A discussion is given in the appendix of the method of measuring these constants by the use of 18 properly oriented crystals.