KONTROLNI ZARIZENI PRO BEZKONTAKTNI KONTROLU, ZEJMENA PRO KONTROLU POVRCHU KONTINUALNE PROCHAZEJICIHO MATERIALU VE FORME PROVAZCE KABELU

摘要

The invention relates to a test instrument for contactlessly testing, particularly for testing the surface of continuous extruded material, preferably of compound Al/Cu conductors. It is the aim and the object of the invention to create a test instrument which can be produced without great technical expenditure with simple means, is insensitive to external influences and indicates errors even at the highest possible operating speeds. According to the invention, the object is achieved by the fact that a test probe, in which a probe inductance and a correction capacitance is arranged, is connected via a connecting cable to an oscillator following which in series a 90 DEG phase shifter circuit is arranged, and the AFC output of the frequency demodulator is connected via an R-C section of large time constant, which is arranged in parallel, to the oscillator and is connected undelayed to a threshold IC which is arranged in parallel and subsequently to an evaluating unit, the probe inductance of the test probe forming a resonant circuit with the capacitance of the connecting cable and the capacitance of the capacitive voltage section including the correction capacitance. IMAGE