further informa tion w e i n v i t e y o u t o d i s c u s s y o u r c u s t o m f o r c e s e n s i n g requirements with us. call us at (714) 639-7810, or e-mail sensors@statek.com. technical p a pers c h u a n g , s h i h s . , f o r c e s e n s o r u s i n g d o u b l e - e n d e d tuning fork quartz crystals , proceedings of the 37th annual frequency control symposium, 1983, pp. 248-254. figure 4: schematic of pressure sensor or scale. figure 3: cross-section of one type of accelerometer . overview statek has designed and manufactured quartz-crystal resonators using photolithographic and chemical milling methods for over three decades and has applied this expertise and capability to now of fer double-ended tuning- fork (DETF) force-sensors, as shown in figure 1. the resonant frequency of the DETF force-sensor is a function of its dimensions, electrode configuration, and the applied force. compression or extension of the sensor causes a corresponding change in frequency , as shown in f i g u r e 2 . o n c e c a l i b r a t e d , m e a s u r i n g t h i s c h a n g e i n frequency gives the applied force. because the DETF force-sensors operate on frequency- based priniciples, they are immune to amplitude noise as well as noise at frequencies other than at the frequency of the sensor . as a consequence, the signals in the system can operate at full amplitude, thereby avoiding the noise that usually plagues low-level measurements. quartz force-sensors of fer further advantages over other force sensing technologies such as sensitivity , small size, low mass and stable performance. w e can customize the size of the sensor to fit your application. s t a t e k c o r p o r a t i o n 5 1 2 n . m a i n s t . , o r a n g e , c a 9 2 8 6 8 7 1 4 - 6 3 9 - 7 8 1 0 f a x : 7 1 4 - 9 9 7 - 1 2 5 6 w w w . s t a t e k . c o m applica tions a c c e l e r o m e t e r s , s e e f i g u r e 3 . p r e s s u r e s e n s o r s , s e e f i g u r e 4 . p r o d u c t i n f o r m a t i o n d o u b l e - e n d e d t u n i n g f o r k s e n s o r s 1 0 1 8 6 - r e v a figure 1: a picture of one of statek s DETF force-sensors fea t ures h i g h l y s e n s i t i v e s m a l l s i z e o p e r a t e s b a s e d o n f r e q u e n c y p r i n c i p l e s h i g h s i g n a l - t o - n o i s e - r a t i o l o w a g i n g d e s i g n e d f o r c u s t o m e r s p e c i f i c a p p l i c a t i o n s figure 2: example of a corresponding change in frequency by applied force. -100,000 -80,000 -60,000 -40,000 -20,000 0 0 1 00 200 300 400 500 600 700 800 applied force (p), grams frequency shift (df/f), ppm d f / f = d p + e p 2 d = 1 2 4 p p m / g r a m e = 0 . 0 1 4 p p m / g r a m 2
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