Abstract: A mixture of two to three ingredients, which ingredients may be stored on their own, are used for the manufacture of a thermochrome lacquer. The first ingredient is a compound of heavy metal or noble metal dispersed in a resin base solution, the second ingredient is a sulfur/carbon-covalent compound dispersed in the resin base solution, or in a hardener for the resin base, and the third ingredient, if required, is the hardener. The resin base is related to the hardener, and the metal compound to the sulfur/carbon covalent compound in respective stochiometric ratios. The metal compound is a metal compound of an oxide forming metal sulfide compounds with the sulfide ions, the metal sulfide compounds being irreversibly darkened, or a metal compound of an inorganic anion, or a metal compound of a monocarboxylic acid, or a metal compound of a dicarboxylic acid. The resin base consists of a prepolymerizate of a methacrylic acid, or of a glycide lather, and the hardener consists of a diol or an amine.

Abstract: A transducer for measuring a current, includes a magnetic core which has a gap substantially impeding passage of any magnetic flux, a coil arranged to pass a premagnetizing current for producing a first magnetic field, a loop for carrying the current to be measured, so as to produce a second magnetic field, and a magnetic field comparision device exposed to the magnetic fields. The magnetic field comparison device includes a magnetic film bridging the flux gap. The film is alternately controllable in respective opposite directions of saturation substantially by the first magnetic field, and evaluates the measuring current in dependence of the magnetic fields. The magnetic core, the coil, the loop, and the magnetic film are substantially disposed concentrically.