@staticmethod
def pt100_voltage_to_temperature(i0, v):
    """Return the temperature relative to (I,V) characteristic of a pt100
        sensor. Note that the response of a pt100 is nonlinear,
        but the expression works well from about -40 to +150 degree Celsius.
        :param i0: current through sensor (float)
        :param v: voltage accross sensor (float)
        :returns: the temperature value (float)
        """
    return 2.604 * v / i0 - 260.4
