Method and circuit arrangement for measuring the diameter of a metal wire

Method and circuit arrangement for measuring the diameter of a metal wire, in which a known constant current (I) is applied to a prescribed length of wire and the voltages (V1, V2) occurring on the current-carrying wire segment are measured, and the diameter (d) of the metal wire (23) is calculated therefrom. According to the invention, the voltages (V1, V2) occurring on the wire segment are measured at two instants following one another at a specific period ( tau ) and the diameter (d) is determined from the known current intensity (I), the period ( tau ), the initial and final voltages (V1, V2) and knowledge of the specific heat (c), the density ( sigma s) of the specific resistance and the product (M) of the specific resistance and the coefficient of thermal expansion of the wire material in accordance with the following relationship: The circuit arrangement contains at least one voltage-controlled current generator whose output is connected to supply leads fed to the metal wire and whose control input is connected via a controlled hold circuit to a voltage generator, which generates a periodically rising analogue output voltage, and a voltage measuring unit, which measures the voltage, present at contacts, of the prescribed metal wire segment, contains the voltage comparators, which detect the initial and final voltages of the metal wire, and a reference voltage stage, and whose output ... on the one hand ... Original abstract incomplete.