PIEZOELECTRIC CRYSTALS IN OSCILLATOR CIRCUITS 



189 



and for the input susceptance 



, CzuiixK{K + Gi) — Qw^CCsco — 5i) 



* = -^'" " (if + o' + (c. - B,y — ('2.46) 



where A' and jx are defined as follows: 



A' = 



— - I (Cy constant) 

 — ( —^ J («p constant) 



and Gi and T^i are the conductance and susceptance of the plate circuit. 

 If we let 



h = 



A = 



— and B= - 



(12.45) becomes 



(1 + ///>) + 



g = C3C0-I 



<^ - 3 



(1 + hBf + 



and (12.46) becomes 



h = — C3C0 



m(1 + /'^) 



1 + 



- -'<^ - 1) 



(12.47) 



(1 + hBY + A 



(■ - -?) J 



(12.48) 



When the resistance of the plate circuit is neglected (i.e. h = 0), and /x » 1 

 we may write 



m(^ - B) 



K ^ \ -\- {A - BY 



(12.49) 



and 



A 



[ m - iJ(.4 - ij) 1 



These equations are in a convenient form to determine the effect of the 

 plate tuning J{B) and grid-plate capacitance f{A ) upon the resistance p 



