2. Hertz, abbreviated as "Hz" in Chinese, is the basic unit of frequency, named in memory of German physicist heinrich rudolf hertz who discovered electromagnetic waves. Hertz is the unit of frequency when electricity, magnetism, sound waves and mechanical vibrations are periodically circulated. That is, cycles per second. 1Hz stands for vibration per second 1 cycle, and 60Hz stands for vibration of 60 cycles per second. Hz is a very small unit, usually preceded by units of order of magnitude such as K (thousands), M (millions) and G (billions).