Title :
High sensitivity low cost capacitive strain gage
Author :
Silva, Losivaldo Godoy da ; De Carvalho, Aparecido Augusto ; de Oliveira Rodriges, R.
Author_Institution :
Dept. of Electr. Eng., Sao Paulo State Univ., Brazil
Abstract :
This paper describes a high sensitivity low cost capacitive strain gage sensor. The theory, design and sensor construction details are presented. It consists of eight capacitive sensors connected in two full bridges. The capacitive strain gage sensor structure was designed in order to produce high sensitivity and low dependence with temperature. By using a simple signal conditioning circuit constituted by a differential amplifier, a band-pass filter, and a precision rectifier the device can measure forces with resolution of 0.009 N and precision of 98.7%. It is rugged, presents linear response, and good repeatability. It presents sensitivity of 8.7 V/N and fall time of 12 ms.
Keywords :
band-pass filters; capacitive sensors; differential amplifiers; rectifiers; signal processing equipment; strain gauges; 12 ms; band-pass filter; capacitive sensors; capacitive strain gage sensor; differential amplifier; good repeatability; high sensitivity strain gage; linear response; low cost capacitive strain gage; precision rectifier; sensor construction; signal conditioning circuit; Band pass filters; Bridge circuits; Capacitive sensors; Costs; Differential amplifiers; Force measurement; Rectifiers; Sensor phenomena and characterization; Temperature dependence; Temperature sensors;
Conference_Titel :
Instrumentation and Measurement Technology Conference, 2004. IMTC 04. Proceedings of the 21st IEEE
Print_ISBN :
0-7803-8248-X
DOI :
10.1109/IMTC.2004.1351063
