burden resistor and/or voltage divider in an energy-sensing CT setup
Here's your circuit: -



R1 and R2 divide the 5V dc supply to give you 2.5V and 2.5V is the mid-position of your ADC input. C1 provides an element of stability to that midpoint preventing 5V dc power supply noise affecting your readings.

The 2.5V lifts the ac voltage from your burden so that it appears as a waveform centred about 2.5V dc - this is what your ADC wants to see.

I'll also add that if you are wanting to measure power in your establishment/home then you need to measure line AC voltage too.