Patent ID: 6541963
Filing Date: 2003-04-01
Classification: G01D

Abstract:
A differential eddy-current transducer adapted for use in means for nondestructive testing electrically conducting and/or ferromagnetic objects, comprising:a primary detector, including: a first search coil having a first lead and a second lead; a second search coil having a first lead and a second lead and constructed similarly to said first search coil; an additional coil having a first lead and a second lead, and connected in series aiding between said first search coil and said second search coil, said first lead of said additional coil being connected to said first lead of said first search coil, and said second lead of the additional coil is connected to said first lead of said second search coil; said differential eddy-current transducer further comprising: an electronic unit, including: a potentiometer having a first lead, a second lead, and a midpoint lead; said first lead of said potentiometer connected to said first lead of said first search coil and to said lead of said additional coil; said second lead of said potentiometer connected to said first lead of said second search coil and to said second lead of said additional coil; a first capacitive element having a first lead and a second lead; said first lead of said first capacitive element connected to said midpoint lead of said potentiometer; an operational amplifier having an inverting input connected to said second lead of said first capacitive element, a noninverting input which is grounded, and an output serving as the output of said electronic unit; a feedback resistance cut in between said inverting input of said operational amplifier and said output thereof; said second lead of said first search coil and said second lead of said second search coil, both being adapted for connecting to a source of alternating voltage applied to said second leads in antiphase.