Abstract: A process for producing high precision electrical resistance elements and electrical resistance elements produced thereby are disclosed. The process includes the step of etching a masked metallic layer bonded to an electrically insulating substrate for a time sufficient to etch away substantially all the masking material and a predetermined portion of the metallic material to produce a high precision electrical resistance element having a predetermined ohmic value. Preferably, the masking material has an erosion rate under ion bombardment greater than the erosion rate of the metallic layer and the thickness of the masking material is established as a predetermined function of the metallic layer to be etched away.

Abstract: A process for etching a thin film or foil of an electrically conductive resistive material, preferably an alloy predominantly comprising nickel and chromium, by electrolytic etching under conditions of electrochemical machining above Jacquet's plateau on the I.V. characteristic curve. The process is particularly suitable for manufacturing a planar electrical resistor having a high stability, a low temperature coefficient, and a high ohmic value despite the relatively low resistivity of the film or foil. The anode surface polarization is maintained substantially constant over the surface of the foil or film by removing the by-products of the etching process, i.e., gases, viscous layers and other impurities, by mechanical effects such as an electrolytic flow or mechanical vibration, or both together. These mechanical effects are carefully balanced against the applied potential values such that the rate of formation of the layers and gases at the anode is equal to their rate of removal.