either the conductive areas 13 or the insulating areas 17 can be moulded in between the in each case areas of the other type using a two component injection moulding process such as is known in plastics processing it is finally also possible from a single per se homogeneous piece of starting material through working individual areas to subsequently make them either electrically conductive or electrically insulating possibilities would e g be offered by thermal or chemical working or irradiation as can be gathered from fig1 and also as a general observation it is advantageous for the sensor element surface 14 and or the electrical contact faces 15 to all be in one plane this simplifies manufacture as a standardized strand material and also facilitates use in certain circumstances it is alternatively advantageous to provide different lengths of conductive areas 13 or insulating areas 17 fig2 shows a variant of a sensor element device 111 which once again has conductive cylindrical elongated areas 113 in fig2 they are provided at the top with a sensor element surface 114 and at the bottom with an electrical contact face 115 differing from the construction according to fig1 the conductive areas 113 are surrounded by material 117 except in the areas where the sensor element surfaces 14 and electrical contact faces 115 are located.