A mobile device for measuring at least one electrical biosignal, the device comprising a first input and a second input , a measuring circuit part for providing an output signal indicating the electrical biosignal to be measured, the measuring circuit part comprising a first input and a second input , a charging circuit part for charging a rechargeable battery inserted in the device , the charging circuit part comprising a first input and a second input , and a microcontroller arranged to execute a firmware arranged to control operations in the mobile device , and that the first input of the charging circuit part is combined with the first input of the measuring circuit part , the first input of the measuring circuit part and the first input of the charging circuit part being connected to the first input of the mobile device , and the second input of the charging circuit part is combined with the second input of the measuring circuit part , the second input of the measuring circuit part and the second input of the charging circuit part being connected to the second input of the mobile device and that the charging circuit part comprises a switching element for switching the charging circuit part to a low-impedance on-state for charging the rechargeable battery inserted in the mobile device and to a high-impedance off-state for the measurement of the at least one electrical biosignal, characterized in that the charging circuit part is arranged to provide a reset signal the state of which is arranged to change when the mobile device is connected to a battery charger device , the reset signal being used to reset and/or stop the microcontroller . a measuring circuit part for providing an output signal indicating the electrical biosignal to be measured, the measuring circuit part comprising a first input and a second input , a charging circuit part for charging a rechargeable battery inserted in the device , the charging circuit part comprising a first input and a second input , and a microcontroller arranged to execute a firmware arranged to control operations in the mobile device , and that the first input of the charging circuit part is combined with the first input of the measuring circuit part , the first input of the measuring circuit part and the first input of the charging circuit part being connected to the first input of the mobile device , and the second input of the charging circuit part is combined with the second input of the measuring circuit part , the second input of the measuring circuit part and the second input of the charging circuit part being connected to the second input of the mobile device and that the charging circuit part comprises a switching element for switching the charging circuit part to a low-impedance on-state for charging the rechargeable battery inserted in the mobile device and to a high-impedance off-state for the measurement of the at least one electrical biosignal, characterized in that the charging circuit part is arranged to provide a reset signal the state of which is arranged to change when the mobile device is connected to a battery charger device , the reset signal being used to reset and/or stop the microcontroller . <EOS>