A solar rooftop system works on the concept of conversion of sunlight into electricity. The phenomenon is known as the photovoltaic effect.
When sunlight falls on the PV cells in a solar panel, the sunlight is converted into electricity. The generated power is DC current. An AC combiner box is used to convert that DC power into usable AC power.
The generated AC electricity is fed into a bidirectional meter that supplies power to the house. It also exports excess power to the DISCOM (grid) and imports power from the grid if electricity generated by the rooftop solar system is not enough to cover the daily requirement.