Apparatus designed to determine and/or monitor at least a process variable of a medium in a vessel with at least - a unit capable of mechanical vibration , and - a drive/reception unit designed to excite the unit capable of mechanical vibration to produce mechanical vibrations using an electrical excitation signal and designed to receive and convert the mechanical vibrations into an electrical reception signal - a control unit , which is designed to generate the excitation signal on the basis of the reception signal, and to set a predefinable phase shift between the excitation signal and the reception signal, - a unit capable of electromagnetic vibration , - an active element designed to generate and/or maintain electromagnetic vibrations in the unit capable of electromagnetic vibration , wherein said active element forms an oscillator together with the unit capable of electromagnetic vibration , - a decoupling unit , which is designed to pick up an output signal via the active element , and - an evaluation unit , wherein said evaluation unit is designed to determine the at least one process variable from the reception signal and/or from the output signal, wherein at least a unit capable of mechanical vibration is provided in the form of a tuning fork with a first fork tine and a second fork tine and at least a unit capable of electromagnetic vibration with at least a first conductive track and a second conductive track , and wherein the first conductive track of at least one of the at least one unit capable of electromagnetic vibration is arranged at least partially in the interior of the first fork tine and the second conductive track of said unit capable of electromagnetic vibration is arranged at least partially in the interior of the second fork tine of the at least one unit capable of mechanical vibration , or wherein the first and the second conductive track of at least one of the at least one unit capable of electromagnetic vibration is arranged at least partially in the interior of the same fork tine of one of the at least one unit capable of mechanical vibration , or wherein the first and/or the second conductive track of at least a unit capable of electromagnetic vibration is arranged inside a housing of the drive/reception unit . - a unit capable of mechanical vibration , and - a drive/reception unit designed to excite the unit capable of mechanical vibration to produce mechanical vibrations using an electrical excitation signal and designed to receive and convert the mechanical vibrations into an electrical reception signal - a control unit , which is designed to generate the excitation signal on the basis of the reception signal, and to set a predefinable phase shift between the excitation signal and the reception signal, - a unit capable of electromagnetic vibration , - an active element designed to generate and/or maintain electromagnetic vibrations in the unit capable of electromagnetic vibration , wherein said active element forms an oscillator together with the unit capable of electromagnetic vibration , - a decoupling unit , which is designed to pick up an output signal via the active element , and - an evaluation unit , <EOS>