A neper (Symbol: Np) is a unit of ratio. It is not an SI unit but is accepted for use alongside the SI. A ratio is a dimensionless, or unitless, quantity denoting an amount or magnitude of one quantity relative to another. ...
Cover of brochure The International System of Units. ...
It is used to express ratios, such as gain and loss, and relative values. The name is derived from John Napier, the inventor of logarithms. In electronics, gain is usually taken as the mean ratio of the signal output of a system to the signal input of the system. ...
John Napier For other people with the same name, see John Napier (disambiguation). ...
Like the decibel, it is a unit in a logarithmic scale, the difference being that where the decibel uses base-10 logarithms to compute ratios, the neper uses base e ≈ 2.71828. The value of a ratio in nepers, Np, is given by The decibel (dB) is a measure of the ratio between two quantities, and is used in a wide variety of measurements in acoustics, physics and electronics. ...
A logarithmic scale is a scale of measurement that uses the logarithm of a physical quantity instead of the quantity itself. ...
Logarithms to various bases: is to base e, is to base 10, and is to base 1. ...
e is the unique number such that the value of the derivative (slope of a tangent line) of f (x)=ex for any value of x is equal to the value of f (x). ...
 where x1 and x2 are the values of interest, and ln is the natural logarithm. The natural logarithm, formerly known as the hyperbolic logarithm, is the logarithm to the base e, where e is equal to 2. ...
The neper is often used to express voltage and current ratios, whereas the decibel was used in early times to express power ratios. Taking that into account we have International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ...
In electricity, current refers to electric current, which is the flow of electric charge. ...
In physics, power (symbol: P) is the rate at which work is performed. ...
  Like the decibel, the neper is a dimensionless unit. The ITU recognizes both units. In the physical sciences, a dimensionless number (or more precisely, a number with the dimensions of 1) is a quantity which describes a certain physical system and which is a pure number without any physical units; it does not change if one alters ones system of units of measurement...
The International Telecommunication Union (ITU; French: Union internationale des télécommunications, Spanish: Unión Internacional de Telecomunicaciones) is an international organization established to standardize and regulate international radio and telecommunications. ...
External links
- What's a neper?
- Calculating transmission line losses
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