Question about the energy monitor with arduino

Hello,

 

I read the source code and there is lot of things I don't understand :

 

  • #define AC_VOLTAGE_DIV_RATIO   11. What is it ?
  • numberOfSamples
  • What is it Ical and Vcal ?
  • double V_RATIO = RATIO_TANSFORMATEUR * AC_VOLTAGE_DIV_RATIO * 5 / 1024 * VCAL;

    double I_RATIO = (long double)CT_TURNS / CT_BURDEN_RESISTOR * 5 / 1024 * ICAL;

Why 5*1024 ?

Thanks