Testing covered current pack in body, esp. IC - by heating covering magneto-optical film to reduce coercivity field strength, cooling and measuring magnetisation

摘要

The method of testing covered current paths in a body (2) which are isolated from the free surface (2a) of the body involves applying a thin film (3) of a magneto-optical material with imposed magnetic anisotropy to the surface (2a) and heating it using a radiation source until the coercivity field strength of the film material in the direction of easy magnetisation is less than that caused by current in each path (10,11). The magnetisation state induced in the film is determined using a magneto-optical detection device when it has been allowed to cool down. USE/ADVANTAGE - For fault location in electronic circuits, esp. integrated circuits. Positive indications are achieved of positions and functional states of individual current paths.