| 摘要 |
<p>PROBLEM TO BE SOLVED: To allow a user to easily recognize a sensitivity setting value resulting from sensitivity adjustment by allowing the detection sensitivity adjustment type detector switch to output sensitivity and a threshold level. SOLUTION: An oscillation circuit 1 is composed of a resonance circuit including a detection coil L1, an amplifier 1a feeding back the output of the resonance circuit and an adjustment resistor circuit 1b being a feedback resistance, and the oscillation circuit 1 is a detection circuit whose oscillation amplitude is changed depending on an external state such as approch of a metallic body. Then a CPU 5 has a sensitivity adjustment means to adjust the sensitivity by changing the resistance of the adjustment resistor circuit 1b and the function of an external disturbance detection means to detect the adjustment range in a state that an external disturbance is in existence and set the resistance of the adjustment resistor circuit 1b depending on a signal from an operation section 6. Furthermore, the CPU 5 outputs the same signal as an adjustment signal given to an adjustment resistor circuit 1b to an adjustment resistance circuit 7. The circuit 7 is configured the same as the circuit 1b. A resistance display circuit 8 detects the resistance of the circuit 7 and displays it on a display device 9. Thus, the user recognizes the set sensitivity.</p> |
