A THERMOSENSITIVE QUARTZ RESONATOR WITH A BUILT-IN MICROHEATER AS A MULTIPURPOSE SENSOR

A design of a thermosensitive quartz resonator with a built-in microheater is suggested. The resonator uses a piezoelement of a special crystal cut and has a very high-temperature sensitivity. Because of the linear temperature- frequency characteristic of the resonator, it can be used as a temperature sensor in a wide temperature range - from -20 to 100°C. The change of the heater's input power at a constant ambient temperature leads to a corresponding resonator's frequency change. Because of the linearity of the resonator's temperature-frequency characteristic the power-frequency dependence is also linear. In such a way the resonator can be utilized as an electrical power meter in the range of 0-400 mW with a sensitivity of about 136 Hz/mW. Using the heater, the resonator can be heated to temperatures higher than the ambient temperature. If the resonator is placed in a path of a flowing liquid, the liquid flow cools the resonator and causes a frequency change, related to the flow rate. The dependence of the resonator's temperature change on the water flow rate at different input powers has been studied in the range of 0.1-1.2 m/s. © 1995 American Institute of Physics.