Why only D.C supply is used in Electronics circuits?

The most basic electronic components are designed by regulating or taking the characteristics based on one direction flow of electrons(electricity). As the AC current does not maintain a unidirectional flow, as it reverses the direction or alternates the direction, the electronic principles are not adhered to.

That is why in electronic components DC electricity is used. Though the main input supply is from AC, it is suitably stepped down and made suitable to the electronic components by necessary accessory utilities built and connected in the equipment circuits.

DC which is direct current ,were most of our electronic components are designed for DC because each components having a particular tasks,while they perform they should get a constant voltage,so that they can work in a precise manner

*AC power which we generate here is 50Hz frequency that means it will come to zero 50 times a second,
But in DC it will be either ON or OFF for the operating electronic device.
*In order to protect electronic components we want a constant voltage as per the specification of design that we will only get from DC