| 摘要 |
<p>A detection device, for detecting a strength of a magnetic field of an object, includes a housing having a center, a first end and a detection end. A permanent magnetic element is suspended above the center of the housing having a first magnetic field strength and an indicator. A biasing permanent magnetic element is disposed at the first end of the housing and has a second magnetic field strength for biasing the indicator toward the first end. A first distance is between the permanent magnetic element and the biasing permanent magnetic element so that a threshold magnetic field strength can be determined from the first magnetic field strength, the second magnetic field strength and the first distance. Thus, when the object is placed approximate to the detection end and the object magnetic field strength is greater than the threshold magnetic field strength, the indicator rotates toward the detection end.</p> |
