F= 1/T T t stands for time.
Frequency is the number of times to complete vibration per unit time, and it is a quantity to describe the frequency of reciprocating motion of vibrating objects, which is often expressed by symbol F or U, and the unit is one second. In order to commemorate the contribution of German physicist Hertz, people call the unit of frequency Hertz for short. Every object has a frequency independent of amplitude, which is determined by the nature of the object itself and is called the natural frequency. The concept of frequency is not only used in mechanics and acoustics, but also in electromagnetism and radio technology. The number of times that alternating current completes periodic changes in unit time is called the frequency of current.