// constructor
    CT(uint16_t turns, uint16_t shunt, uint8_t calibre, uint8_t pin);
    /**
        turns: the number of turn (coil) on the secondary of the transformer
        shunt: the value of the shunt resistor used on the secondary
        calibre: the max current the sensor is able to measure
        pin: the analog input the output of the sensor is connected to
    **/

    float calibrate();
    /**
        get the offset value of the sensor

        *Note:* The calibration should be done while the sensor is not under 
                load
    **/

    float getRawData();
    /**
        read raw data from the sensor. Raw data is meaningless
    **/ 

    float read(uint8_t unit);
    /**
        read a single measurement
        
        unit:
                (predefined constants)
            mA : read the current in milliampere
            A  : read the current in ampere
            MAX: read the max value of the current
            MIN: read the min value of the current
    **/

    float getMax(uint8_t unit);
    /**
        read the max value of the current

        unit: 
                (predefined constants)
            mA: read max value in milliampere
            default unit: Ampere
    **/

    float getMin(uint8_t unit);
    /**
        read the min value of the current

        unit: 
                (predefined constants)
            mA: read max value in milliampere
            default unit: Ampere
    **/

    float getOffset();
    /**
        read the offset value of the sensor
    **/