| 摘要 |
PURPOSE:To miniaturize this device, and to produce the device in a thin type, by giving alarms according to the magnitude of an outside magnetic field by detecting said magnetude without using a special detecting element by utilizing a coil of a motor as a detecting element of an alternating current magnetic field. CONSTITUTION:This device amplifies voltage induced to a coil of a motor by an outside magnetic field without using a special amplifier by alternatively connecting a low-impedance element and a high-impedance element such as a low-resistance and a high-resistance in both ends of the coil, and facilitates the detection of the presence of the outside magnetic field. Detected signals are amplified by alternatively switching a closed loop of the motor 20 and N gates 23, 24 and a closed loop of the motor 20, a detecting resistance 29 and N gates 26, 25 when the motor is not driven. Alarms can be generated by using detected signals amplified, or it is possible that this watch is made difficult to stop in the outside magnetic field detected. |
