**Neper. **Relative unit of measurement frequently used in the field of __telecommunications__ , through which relationships between __voltages__ or __currents__ can be expressed . Its symbol is Np.

Summary

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- 1 Origin
- 2 Definition
- 3 Equivalence with the unity of the International System
- 4 Note on terminology
- 5 See also
- 6 Reference
- 7 Source

Origin

The neper, also known as the neper, owes its name to __John Napier__ , born in __Edinburgh__ , __Scotland__ , in __1550__ , who died in the same city in the year __1617__ , went down in history as a famous mathematician for the invention of __logarithms__ and of various contributions to different branches of __mathematics__ : __geometry__ , __trigonometry__ , __algebra__ and what at that time were called commercial mathematics. He invented what is known as Napier strips which was an instrument to multiply that later became popular and that several men of the __Renaissance__They used, throughout __Europe__ , as a very useful calculation tool.

Definition

Neper ^{1} : Unit used to express the ratio of two __powers__ , equivalent to 0.868 6 bel (1 bel equals 1,151 neperes).

- The neper allows evaluating the ratio of two
__voltages__or two electronic__powers__, of two__pressures__, etc., according to the formula:

**N (in neper) = log p1 / p2**

In which p1 and p2 are the two __pressures__ or other considerable magnitudes.

The neper is mainly used to evaluate acoustic intensities and the attenuation and amplification of telephone currents. Although the neper is not a unit of measurement of __the International System__ , its use is widely accepted in many countries, for the same purposes as the __decibel__ . The fundamental difference between the two units is that while the __decibel__ is based on the __logarithm__ decimal relationship of magnitudes, the neper what is the __logarithm__ natural and neperiano of said ratio.

Equivalence with the unity of __the International System__

In the __International System__ the unit of measurement is the __decibel__ , it is the tenth of 1 bel; The following table shows an equivalence relationship between both units:

Neper (Np) |
Decibel (dB) |

8.68 Np | 1 dB |

477.72 Np | 55 dB |

521.15 Np | 60 dB |

Terminology Note

This unit of __the International System of Units__ is named after __John Napier__ . In units of measurement whose name comes from a person’s own name, the first letter of the symbol is capitalized (Np), while its name always begins with a lowercase letter (neper), except when it starts a phrase or a title.