Patent ID: 6316845
Filing Date: 2001-11-13
Classification: G01N

Abstract:
An electromagnetic yoke for electromagnetic particle inspection, comprising:a first battery means for supplying a predetermined positive voltage to said electromagnetic yoke;a second battery means for supplying a predetermined negative voltage to said electromagnetic yoke;switching means for switching from said first battery means to said second battery means and back to said first battery means to complete a cycle, said switching means continuously performing said switching at a predetermined number of cycles per second;said switching means including a first drive transistor means dedicated to switching said positive DC voltage on and off and a second drive transistor means dedicated to switching said negative DC voltage on and off; anda clock means for providing a timing pulse of predetermined frequency that controls operation of said first and second drive transistor means;whereby a square waveform that emulates a sinusoidal alternating current waveform is produced;whereby a ferrous article under inspection is demagnetized at the conclusion of the inspection.