摘要 |
PURPOSE:To suppress the equivalent inductance to its minimum, by providing a main electrode having a larger area than one main electrode, and setting on said electrode the frequency adjusting electrode range whose area is equal to or larger than that of the one main electrode. CONSTITUTION:The main electrode 6 having a larger area than the main electrode 5 is stuck and formed so that it is opposed to both the surfaces of the quartz plate 1, and on this main electrode 6, the frequency adjusting electrode range 7 whose area is equal to or larger than that of the one main electrode 5 is set. In this way, since the frequency adjusting electrode range 7 is set so as to be equal to or larger than the main electrode 5, the influence by the energy shut-in effect is reduced even if the frequency is adjusted by sticking a mass substance to this part. Therefore, a variation (increase) of the equivalent inductance is suppressed to its minimum. |