PURPOSE: To acquire and inexpensive device which can be automatically assembled by using an automatic inserting device and of which number of assemblies can be reduced by providing it with a toroidal core, a specified printed wiring substrate and an insulating type jumper resistance.

CONSTITUTION: A device is provided with a toroidal core 1, conductive patterns 5, 6 whereto the core 1 is attached and which has lands 5a, 6a positioned at an area near the attached toroidal core 1 and a printed wiring substrate 3 which is provided with a number of through-holes 7, 8 positioned inside the lands 5a, 6a. In the device, a bendable rod-like conductor 12 is made to pass through an insulator 11, the insulator 11 is brought into contact with the toroidal core 1, both end parts of the conductor 2 which are made to pass through the through-holes 7, 8 are electrically connected with the lands 5a, 6a and attached to the printed wiring substrate 3, and a number of insulation type jumper resistances 9, 10 are provided which form a coil which surrounds the toroidal core 1 together with the conductive patterns 5, 6.