EDDY CURRENT TYPE FLAW DETECTOR

摘要

PURPOSE:To improve S/N by providing an eddy current type flaw detector adapted to convert a signal obtained from a differential excitation coil into DC signals intersecting each other in vector by a phase discrimination with a circuit for detecting hourly variation rates of said DC signals. CONSTITUTION:An excitation coil at a detector section 2 is excited with an exciting power source 1. Signals from the detector section 2 are fed to a phase discrimination circuit 4 passing through an adder 3 and converted into DC signals (signal X and signal Y) intersecting each other in vector. As the flaw signal S changed more rapidly in terms of time than the noise N, the signal X and the signal Y are fed to a variation rate detection circuit 30 to detect the hourly variation rate. The signal of the hourly variation rate is fed to a setting circuit 31, which controls a sampler 32 by logical operation.