Title :
Quartz sensor for water absorption measurement in glass-fiber resins
Author :
Matko, Vojko ; Koprivnikar, Joze
Author_Institution :
Fac. of Electr. Eng. & Comput. Sci., Maribor Univ., Slovenia
fDate :
10/1/1998 12:00:00 AM
Abstract :
The humidity sensor using the sensitive capacitive-dependent crystal is described. Presented is the probe sensitivity (dependence of df on the dCx). In addition, the new idea of excitation of the entire humidity sensor with stochastic test signals is described, and the humidity surface-measuring method is given. The latter includes the influence of test signals on the weighting function uncertainty. The results of the air-humidity measurement and water absorption measurement in glass-fiber resins are shown experimentally. The uncertainty of the surface humidity measurement is less than 0.1% (T=15-25 °C and air-humidity=50 to 98%)
Keywords :
capacitive sensors; crystal oscillators; glass fibre reinforced plastics; humidity measurement; humidity sensors; measurement uncertainty; moisture measurement; sorption; 15 to 25 C; SiO2; direct digital method; glass-fiber resins; humidity sensor; humidity surface-measuring method; probe sensitivity; quartz oscillators; quartz sensor; sensitive capacitive-dependent crystal; sensor excitation; stochastic test signals; surface humidity measurement; water absorption measurement; weighting function uncertainty; Absorption; Capacitance; Capacitive sensors; Frequency; Humidity measurement; Probes; Pulse width modulation; Resins; Stability; Temperature sensors;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
