| 摘要 |
PURPOSE:To set an oscillation frequency freely, by optionally selecting a variable resistance value which has been provided between a common terminal of a ceramic resonator and an earth terminal. CONSTITUTION:Electrodes 2, 3 are provided on the upper and lower parts of a piezoelectric ceramic 1 which has been pllarized in the direction of thickness, the electrode 2 is divided into two by making a slit 4 in the center, leader lines 5, 6 are provided, and a resistance 14 is connected between a common electrode 3 and earth. When this circuit is shifted from a resonance frequency f0, it becomes inductive (L) or capacitive (C), and when the resistance 14 is R, the phase difference of the whole circuit becomes theta=tan<-1>omegaL/R or theta=tan<-1>/omegaCR. Accordingly, a filter characteristics, that is to say, a resonance frequency is set by selecting R optionally. |
