relation to fig2 the controller controls the heating element 47 which forms the actuator 44 of the moisture generator 40 depicted in fig2 in such a way that more or less moisture is released by the moisture generator 40 depending on the values established by the sensors 41 and 42 thus the moisture content of the microclimate between the outer surface 38 of the electrode 37 and the skin of the subject is controlled or regulated in such a targeted manner that a reliable electrocardiographic measurement signal with good signal quality is recorded via the outer surface 38 of the electrode 37 fig6 depicts a further sensor 53 according to a further embodiment in which the moisture generator 40 comprises a liquid reservoir 51 and a pump 54 which pumps liquid from the reservoir 51 the water pumped from the reservoir 51 the pump 54 is conducted to the electrode inner surface 39 by a material 55 which can conduct or wick liquid e g a sponge such that said inner surface is moistened although this has not been depicted in fig6 the moisture sensor 41 is connected to the controller 43 described in relation to fig2 the controller controls the pump 54 which forms the actuator 44 of the moisture generator 40 depicted in fig2 in such a way that more.