EDDY CURRENT TESTING (ECT)
EDDY CURRENT TESTING (ECT) Eddy current testing (ECT) as a technique for testing finds its roots in electromagnetism . Eddy currents were first observed by François Arago in 1824, but French physicist Léon Foucault is credited with discovering them in 1855. ECT began largely as a result of the English scientist Michael Faraday 's discovery of electromagnetic induction in 1831. Faraday discovered that when there is a closed path through which current can circulate and a time-varying magnetic field passes through a conductor (or vice versa), an electric current flows through this conductor. In 1879, another English-born scientist, David Edward Hughes , demonstrated how the properties of a coil change when placed in contact with metals of different conductivity and permeability, which was applied to metallurgical sorting tests. Although there were a number of encouraging developments in the ...