| frequency where the admittance value of a lossless resonator becomes zero|
Note 1 to entry: When the electromechanical coupling factor is low, an approximate value of the frequency is given by the expression
where C0 represents the shunt capacitance and L1 and C1 the motional inductance and the motional capacitance respectively. The expression can be derived from Figure 2 by letting R1 = 0.
Figure 2 – Equivalent circuit of a piezoelectric vibrator (one-port resonator)
Note 2 to entry: This entry was numbered 561-02-11 in IEC 60050-561:1991.