| 摘要 |
PURPOSE:To excite stably a fundamental wave by adopting the length of the exciting electrode of an oscillating chip as 0.8+ or -0.05 of the length of the chip so as to suppress sub oscillations of 5th and 7th orders as well as the 3rd harmonics. CONSTITUTION:An exciting electrode 1 is provided to the front and rear faces of the rectangular crystal oscillation chip 1 and is connected to a fixed part 3 of the end face of the chip 1 by a connection section 4. In applying an alternate electric field to the electrode 2 of the chip 1, the cut angle is decided to apply thickness-shear oscillation and the length of the electrode 2 is selected to 0.8+ or -0.05 of the length of the chip 1. Then the length minimizing the sum of electric charges for the 3rd, 5th and 7th harmonics is selected depending on the relation between the length of the electrode and the electric charge of the sub oscillation.
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