| 摘要 |
PROBLEM TO BE SOLVED: To provide a non-power supply type radio wave sensor terminal and radio wave transmission method that do not increase transmission frequency even if a current value of a measured current is large, and are downsized.SOLUTION: When a resistance voltage division voltage Vof a voltage Vof a connection point between a current limit resistance Rand a threshold determination capacitor Cis equal to or more than a reference voltage V, an analog switch 121 is turned on, the voltage Vis applied to a radiowave transmission unit 13 as a power voltage, and the radio wave transmission unit 13 wirelessly transmits a transmission signal. A transmission interval Tof the transmission signal is expressed by a following expression: T=CRlog{(V-V)/(V-V)}, where in the expression, Cis denoted as a capacitance value of the capacitor C, Ras a resistance value of resistance R, Vas an output DC voltage of a Cockcroft-Walton circuit 111, Vas a value of the voltage Vat a time when an operation of the radio wave transmission stops, and Vas a value of the voltage Vat a time when the operation of the radio wave transmission starts.SELECTED DRAWING: Figure 1 |
