A sensor of a measuring device for detecting a mass flow, a viscosity, a density, and/or a variable derived therefrom of a medium flowing through at least one measuring tube of the sensor, comprising: - the at least one measuring tube with an inlet and an outlet, said tube being configured to conduct the medium between the inlet and outlet; - at least one vibration generator (3.11) which is configured to cause the at least one measuring tube to vibrate; and - at least two vibration sensors (3.1, 3.111) which are configured to detect the deflection of the vibrations of the at least one measuring tube, wherein at least one vibration generator (3.11) and the vibration sensors (3.1, 3.111) each have a coil device with at least one coil in each case, and at least one magnetic device in each case, wherein the magnetic device and the coil device can be moved relative to each other, wherein the magnetic device and the coil device of a vibration generator (3.1) or vibration sensor (3.1, 3.111) are configured to interact with each other through magnetic fields, wherein the coil device comprises a PCB with at least one PCB layer, wherein each PCB layer has a first lateral surface and a second lateral surface which is plane-parallel to the first lateral surface; wherein the coil is configured to detect or generate a time-varying magnetic field, wherein the coil is formed by an electrically conductive trace in at least sections, wherein the coil is arranged on the first lateral surface and/or second lateral surface of a PCB layer, wherein the PCB comprises at least two contacting elements for connecting the coil to an electronic measuring and/or operating circuit of the measuring device using connecting elements; characterized in that at least one contacting element has a hole, wherein the PCB has at least one indentation with a base, wherein each contacting element on the base is assigned to an indentation, wherein the connecting element is arranged in the indentation, wherein the indentation is at least partly filled with a solid metallic microparticle mass which creates a material bond between the connecting element and the PCB and the contacting element and transfers electrical contact between the connecting element and the contacting element. - the at least one measuring tube with an inlet and an outlet, said tube being configured to conduct the medium between the inlet and outlet; - at least one vibration generator (3.11) which is configured to cause the at least one measuring tube to vibrate; and - at least two vibration sensors (3.1, 3.111) which are configured to detect the deflection of the vibrations of the at least one measuring tube, wherein at least one vibration generator (3.11) and the vibration sensors (3.1, 3.111) each have a coil device with at least one coil in each case, and at least one magnetic device in each case, wherein the magnetic device and the coil device can be moved relative to each other, wherein the magnetic device and the coil device of a vibration generator (3.1) or vibration sensor (3.1, 3.111) are configured to interact with each other through magnetic fields, wherein the coil device comprises a PCB with at least one PCB layer, wherein each PCB layer has a first lateral surface and a second lateral surface which is plane-parallel to the first lateral surface; wherein the coil is configured to detect or generate a time-varying magnetic field, wherein the coil is formed by an electrically conductive trace in at least sections, wherein the coil is arranged on the first lateral surface and/or second lateral surface of a PCB layer, wherein the PCB comprises at least two contacting elements for connecting the coil to an electronic measuring and/or operating circuit of the measuring device using connecting elements; characterized in that at least one contacting element has a hole, wherein the PCB has at least one indentation with a base, wherein each contacting element on the base is assigned to an indentation, wherein the connecting element is arranged in the indentation, wherein the indentation is at least partly filled with a solid metallic microparticle mass which creates a material bond between the connecting element and the PCB and the contacting element and transfers electrical contact between the connecting element and the contacting element.