What is a transformer?!!

The transformer is a static electric machine (because it contains no moving parts) belonging to the broader category of converters. In particular the transformer to convert the parameters of voltage (V symbol unit [V] volts) and current (symbols The unit [A] amperes) input than output, while maintaining constant the amount of power electrical (less the losses due to hysteresis and eddy currents). The transformer is a machine able to operate only in alternating current, because it exploits the principles of electromagnetism linked to variable flows. The transformer has paramount importance in today's world: without it, the electricity transmission grids that connect power plants to millions of homes and industries could not function