Eddy Currents are electrical currents that are produced from a reaction with magnetic fields. A materials chemistry and temperature affect its permeability. Several sophisticated instruments are typically employed during a NDT eddy current test, including a meter display instrument, an impedance plane display instrument, a linear time base display instrument and a bargraph display instrument. When used in conjunction with a eddy current test, you can determine surface and sub-surface abnormalities. Corrosion, surface inconsistencies, bolt hole issues and other potential problems can typically be detected by using eddy current.