Abstract: A thickness, shear crystal resonator and a method of manufacturing therefor in which a natural crystal surface is appeared on at least a part of surfaces of crystal plate thereof to the extent that the part is made substantially transparent, the impedance of the crystal resonator is made small thereby and a large Q factor can be obtained. And, there is found no dip in the temperature characteristics of the impedance and the vibrating frequency of the crystal resonator.

Abstract: A crystal oscillator for generating an output oscillation whose frequency is maintained constant independently of the variation of temperature including a first quartz vibrator arranged in a heating unit which includes a thermostat and vibrating at a fundamental frequency, a second quartz vibrator arranged also in the same heating unit and vibrating at a third overtone frequency, a frequency multiplying circuit for multiplying the fundamental frequency by three, a frequency comparator for comparing the fundamental frequency multiplied by three with the third overtone frequency to derive a frequency difference which represents a temperature of the thermostat, and a temperature controlling circuit for controlling the temperature setting of the thermostat in accordance with the detected frequency difference. Any one or both of the fundamental and third overtone oscillations may be derived as an output oscillation.

Abstract: A piezoelectric vibrator of thickness-shear mode including a vibrating plate made of AT-cut quartz and a pair of electrodes applied on major surfaces of the vibrating plate in opposition to each other. A part of a contour of the vibrating plate is made closer to the electrode by cutting off a corner of a square vibrating plate. An impedance of the piezoelectric vibrator for a fundamental vibration is extremely increased to suppress the fundamental vibration and thus the piezoelectric vibrator can vibrate stably at a third overtone frequency.

Abstract: The disclosed temperature-compensated crystal resonator unit has a crystal resonator element with a first ceramic member attached thereto, which resonator element is housed in a vessel with a second ceramic member being mounted on the housing and electrically connected to said first ceramic member in series thereto, both of said first and second ceramic members having positive temperature coefficients of electric resistance, said second ceramic member being mechanically separated from both the first ceramic member and the crystal resonator element.