HIGH-FREQUENCY OSCILLATION TYPE PROXIMITY SENSOR

摘要

PROBLEM TO BE SOLVED: To provide a high-frequency oscillation type proximity sensor having a simple constitution wherein a high-frequency oscillation circuit having a sensing coil can be brought into a soft-oscillation circuit. SOLUTION: The high-frequency oscillation type proximity sensor has a sensing circuit 1 constituting a portion of a high-frequency oscillation circuit; a nonlinear amplifier 2 connected with the sensing coil which constitutes the high-frequency oscillation circuit for driving and oscillating the sensing coil, and which changes the oscillation amplitude generated in the sensing coil correspondingly to the change of the Q of the sensing coil; and a compensation circuit for compensating the characteristic of the sensing coil by so feeding back to the sensing coil the oscillation output voltage generated in the sensing coil as to rotate its phase.