Extent of electrical conductor fissure opening measuring device - has differential amplifier, and oscillator controlled synchronising circuit for application and interruption of current flow

摘要

The depth and length of an open fissure in surface of solid electrical conductor is determined by studying variations in electrical resistance. A constant current is circulated and voltage measurements made adjacent to the fissure. An electrical conductor (1) with fissure (f) is connected (2, 3) to constant current generator (4). Measuring contacts (5, 6) adjacent to fissue enable voltage to be sensed and applied to differential input amplifier (7). An oscillator (11) controlled sync. circuit (10) causes application and interruption of current flow and the measured voltage values are stored in memory of measuring circuit (8) for calculation and display of resistance value.