By measuring instruments there are increased requirements in terms of accuracy of measurements, performance devices, increase their reliability, reduce weight and dimensions, power saving. The principles of operation of the bulk of instrumentation are based on the work of the primary converters. Thermomagnetic sensor consists of two sensing elements and the magnetic system. The sensing element is a spiral of 5-6 turns of wire with a thickness of 10-12 microns in a thermally fused shell of 1.0-1.5 mm. Such a sensor has a small size, which allows them to be installed in any location of the magnetic system. Sensing elements should be placed in locations where the product HdH/ds maximum. Experiments were carried out to determine the effect of temperature and pressure of nitrogen-oxygen mixture to the testimony of the thermomagnetic sensor at a supply voltage of 5 V. The temperature of the gas mixture was varied in the range from minus 30 to 30 °C in steps of 10 °C with the camera heat-cold KTKh-74. It was found analytical formula f = y (x), which approximates the experimental (tabular) dependence using the first-degree polynomial y (x) =kx + b. Results of experimental studies give reason to believe that the thermomagnetic sensor is the most promising for the analysis of a wide range of oxygen at high temperature and pressure of the gas mixture and outperforms known examples of sensors for oxygen. Using as a sensing element microspiral of cast microwire can significantly improve the performance of the thermomagnetic analyzers.