The theory, design and preliminary test results of a new constant resistance type flow velocity / flow rate sensor are presented. The interface circuit for a flow velocity / flow rate sensor which converts the error signal from sensing element and fee...
The theory, design and preliminary test results of a new constant resistance type flow velocity / flow rate sensor are presented. The interface circuit for a flow velocity / flow rate sensor which converts the error signal from sensing element and feedbacks to the sensor is described. Main problems of previous flow velocity / flow rate sensors are: 1)it is difficult to measure flow velocity when the temperature of fluid changes, 2)fabrication process is complicated, and 3)a measurement isn't easy when the temperature of fluid is higher than that of chip. These defects result in difficulty of commercialization of the solid state flow sensor. In this paper, a new flow sensor was designed only with thin film resistor and OP-Amps, which can be fabricated on one chip using solid state technology. It Is not only simpler than previous sensors in the aspect of production process, but also can measure the flow velocity with no relation of fluid temperature or temperature change.