Abstract: A galvanically isolating circuit for converting input voltage which is in a first potential to an output variable which is in a second potential. The circuit is characterized by a first input terminal and a second input terminal for receiving the input voltage in the first potential, and a first output terminal and a second output terminal in the second potential for generating the output variable. The circuit is further characterized by a serial capacitance section for providing galvanic isolation between the input terminals and the output terminals, first polarity switching means, which are arranged to operationally connect the input terminals to the serial capacitance section by periodically reversing the polarity, and second polarity switching means, which ate arranged to operationally connect the serial capacitance section to output terminals by periodically reversing the polarity, in synchronism with the first polarity switching means.

Abstract: A converter system is comprised of an analog-to-digital converter (1) and a digital-to-analog converter (2). A first base number of a number system used in the analog-to-digital converter is less than 2, and a second base number of a number system used in the digital-to-analog converter is less than two. The first base number does not equal the second base number. For example, both are within a range from 1.90 to 1.99. In a calibration method the output of the digital-to-analog converter is switched to the input of the analog-to-digital converter, and a controller (3) provides digital values to the input of the digital-to-analog converter, and receives corresponding digital values from the output of the analog-to-digital converter.