PURPOSE: To enable stable detection regardless of the magnitude of magnetic fluxes by converting the magnetic flux generated from a bipole converter of a hand type electronic watch to an analog electric signal, holding and voltage- dividing the max. value of the electric signal and setting a suitable reference value.
CONSTITUTION: An electromotive voltage is generated from the magnetic flux generated in a sensor coil 9 from the magnetic flux generated from the bipole converter of the hand type electronic watch. The electromotive voltage from the sensor coil 9 increases and the voltage stored in a capacitor 10 for charging increases as well if the magnetic flux generated from the bipole converter is large. The threshold value in a comparator circuit 4 increases similarly as well. The electromotive voltage from the sensor coil 9 decreases and the voltage stored in the capacitor 10 decreases as well if the magnetic flux generated from the bipole converter of the hand type electronic watch is small. The threshold value in the circuit 4 decreases similarly as well. Since the threshold voltage fluctuates with the magnitude of the magnetic flux generated from the bipole converter in such a manner, the stable detection is enabled regardless of the magnitude of the magnetic flux.
KOBAYASHI GORO
MURAKAWA KAZUHIKO