Abstract: A remote data read system includes a plurality of accumulators including first transmission/reception sections of an electromagnetic induction type, and a handy terminal including a second transmission/reception section of an electromagnetic induction type. The plurality of accumulators accumulate accumulation values representing amounts of consumed power, gas, tap water, or the like, and output accumulated value data in response to data request signals transmitted thereto. The first transmission/reception sections receive external data request signals, and output accumulation value data in response to the data request signal. The handy terminal outputs the data request signal to read an accumulation value from the accumulator and displays input accumulation value data. The second transmission/reception section outputs the data request signal to the first transmission/reception section, and receives the accumulation value data output from the first transmission/reception section.

Abstract: A zero point compensating circuit for a microbridge flow meter including an upstream thermal sensor means, a downstream thermal sensor means and a heater means located between said upstream and downstream thermal sensor is provided which comprises a first switch coupled to said heater for turning on and off the same and a current supply circuit coupled to said upstream and downstream thermal sensors for selectively supplying the same with a first current when said first switch is closed and a second current larger than said first current when said first switch is opened such that said upstream and downstream thermal sensors reach a temperature to which they are heated when said heater is on in no flow condition. Thus, an offset caused by discrepancy in the resistance value and thermal coefficients of resistance (TCR) of the upstream and downstream temperature sensors can be removed by the above circuit, thereby making it possible to achieve a precise measurement of small flow rates of a fluid of interest.

Abstract: A temperature compensating circuit having a third temperature sensor element for detecting an ambient temperature disposed on the same substrate on which first and second temperature sensor elements are located, and a voltage across the third sensor element, generated by supplying a current thereto, is applied to the first and second sensor elements. Therefore, a voltage applied to first and second sensor elements is automatically changed corresponding to change in ambient temperature, and accordingly a difference in temperature between first and second sensor elements can be precisely detected in a form of voltage signal.

Abstract: This flow meter uses two known flow responsive techniques and combines them in a unique structure and system to form an improved flow meter whose range extends from low to high flow rates. The meter comprises a flow tube with a region of reduced diameter between its inlet and outlet. A microbridge flow sensor of a suitable type known in the art, which responds to thermal changes caused by changes in the flow rate, is located in the region of reduced diameter. A post downstream of the microbridge sensor creates Karman vortices whose frequencies are a function of flow rate and which are detected through ports in the tube by a suitable detector. The output of the microbridge is linear from low flow rates to a mid range and the Karman flow meter output is linear from the mid range to high flow rates. A correction factor is applied to the thermal flow meter output.

Abstract: A bridge balancing circuit includes a bridge having a resistance change type sensor, a differential amplifier for extracting a voltage difference across two central nodes of the bridge, a comparator connected to the output terminal of the differential amplifier, a D/A converter an output terminal of which is connected to one of the two central nodes, and a controller for controlling the D/A converter. The differential amplifier and the comparator automatically detect a balanced point of the bridge, and the controller maintains a balanced state of the bridge.