ZERO TEMPERATURE COEFFICIENT QUARTZ CRYSTALS 



373 



80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 

 TEMPERATURE IN DEGREES CENTIGRADE 



Fig. 3 — Frequency temperature curve for a crystal cut at an angle of +36°26' rotation. 



10,004 



Q 



2 



O 



^ 10,003 



to 



cr 



OJ 

 CL 



(/) 10,002 



OJ 



_i 

 o 

 > 

 u 



Z 10,001 



o 



2 

 LXJ 



g 10,000 



LU 



9,999 



X 



80 90 100 no 120 130 140 150 160 170 180 190 200 210 220 230 240 250 

 TEMPERATURE IN DEGREES CENTIGRADE 



Fig. 4 — Frequency temperature curve for a crystal cut at an angle of +36°30' rotation. 



dieted. If we plot the temperature for zero coefficients against angle of cut 

 it is seen that a maximum temperature of 190° occurs at 36°26' and angles 

 on either side of this have lower temperatures for zero coefficients. Hence 

 this is the maximum temperature that can be reached by an AT type crys- 

 tal. 



