Neper

neper

The unit of measurement based on Napierian logarithms that represents the ratio between two values, such as current or voltage.

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neper [′nē·pər]

(physics)

Abbreviated Np. Also known as napier.

A unit used for expressing the ratio of two currents, voltages, or analogous quantities; the number of nepers is the natural logarithm of this ratio.

A unit used for expressing the ratio of two powers (even when this ratio is not the square of the corresponding current or voltage ratio); the number of nepers is the natural logarithm of the square root of this ratio; to avoid confusion, this usage should be accompanied by a specific statement.

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Neper 

a unit used for expressing the ratio of two physical quantities of the same kind, the number of nepers being the natural logarithm of such a ratio. The neper is named after John Napier and abbreviated Np. The neper is defined as follows: 1 Np = In (F₂ / F₁) if F₂ / F₁ = e, where F₂ and F₁ are physical “force” quantities, for example, voltages, current strengths, and pressures, and e is the base of the natural system of logarithms. Nepers are used mainly for measuring attenuation (damping) of electric signals in communication lines. A neper is related to other logarithmic ratios by the following formulas: 1 Np = 2 log e bel ≈ 0.8686 bel = 8.686 decibels.