| 摘要 |
A magnetic detector comprises a magnetic sensor (16) having a detecting coil (18) on a ferromagnetic core (17), an exciting signal generating circuit (11) which supplies an ac exciting current having a predetermined effective value to the detecting coil (18) of the magnetic sensor (16) via an impedance element (15) to saturate the core (17), a waveform shaping circuit (19) that normalizes the waveform of detected signal taken out from both terminals of the detecting coil (18) using a predetermined threshold value, and a counter (20) that measures the pulse width of normalized signals output from the waveform shaping circuit (19), in order to detect the intensity of the external magnetic field based on a change in the pulse width caused by the external magnetic field that intersects the magnetic sensor (16). |
