8

• This catalog has only typical specifications because there is no space for detailed specifications. Therefore, please review our product specifications or consult the approval sheet for product specifications before ordering.

(Note 1)

The relationship between the size of the resonator

and the resonant frequency is described as follows.

For example, the frequency doubles if the thickness

doubles, when thickness vibration is used.

The following relationship is obtained when the

length of the resonators is ℓ, the resonance

frequency is Fr, the speed of sound waves travelling

through piezoelectric ceramics, and the wavelength

is λ.

Fr. ℓ = Const.

(frequency constant, Fr.t for the thickness)

λ = 2 ℓ

C = Fr.λ = 2Fr. ℓ

As seen in the above formula, the frequency

constant determines the size of the resonator.

(Note 2)

simplification, the impedance Z (ω) between two

terminals is expressed by the following formula.

2

Fig. Ⅰ

Amplitude

Range of

Standing

Wave

(Min.Amplitude) (Max.Amplitude)

Fig. Ⅱ

1

)

Z (ω) =

When ω =

1

1

)

1

)

=

= ωr, Z (ωr) =0

1

1 +

1

1

When ω =

Therefore from ω =2πF,

Fr = ωr/2π =

1

Fa = ωa/2π =

= Fr 1+

= ωa, Z (ωa) = ∞

1

Notes

P17E.pdf

2012.10.31