Reference value

The reference value is in many fields of a particular numerical value which to compare is used.

General

For example, all information in percent is based on a reference value. If this is not specified, misunderstandings or contradictions can easily arise. If 20% of the population of a country is affected by poverty , the population (total population) is the reference value:

${\displaystyle {\text{Prozentsatz}}={\frac {\text{Vergleichswert}}{\text{Bezugswert}}}\cdot 100\,\%}$.

The comparison value is the number of people affected by poverty, the reference value is the total population, the percentage is called the poverty rate .

Use in physics and technology

In the physical-technical context, the following uses are highlighted in the specialist literature :

• In measurement technology as well as in quality assurance and statistics, the reference value is a clearly defined value to which reference is made to define a result deviation ( measurement deviation ). The reference value can be, for example, the upper limit of a measuring range , the scale length or any other clearly defined value. In particular, depending on the definition or agreement, it can be the true , correct or expected value .

• Furthermore, in measurement technology, a measurement can be viewed as a comparison with a reference value, the associated unit of measurement being used as the reference value .

• A reference value is always required for logarithmic quantities , a power quantity or a power root quantity being related to a variable or fixed value before the logarithm is formed, for example in the case of the voltage level . The definition of the fixed size is arbitrary for each application. In audio technology in particular, various reference values ​​are standardized for clear understanding , see reference value (acoustics) .

• On closer inspection, many material constants turn out to be dependent on influencing variables . Then they are given at a fixed reference value. As far as deviations of the constants can be indicated, these are determined from the reference value. Example: Influence of temperature of the specific resistance .

The variable to be compared is often related to the reference value via a difference (e.g. for the measurement deviation), but the values ​​can also be linked via a quotient (e.g. for the ratio) or a quotient of the difference to the Reference value (e.g. for the relative error limit ).

Further subject-specific uses

In various specialist fields, the term reference value, possibly also called reference value, is defined in a special way, or it is replaced by a whole reference system of many individual reference values.

Such reference values ​​can be:

• in medicine : reference values ​​for body functions and chemical-biological analyzes - as an orientation as to whether measured values ​​are to be regarded as pathological;
• in banking : the base value , the key rate , the reference rate or the base rate ;
• in geodesy the "mean earth figure 1980" in the form of the reference system GRS80 ;
• In astronomy , the classic polar star was 2.1 mag, the photometric zero point of the apparent brightness.

See also

• Calibration , normal value
• Standard conditions
• Fundamental constant , gravity network

Individual evidence

1. ↑ IEC 60050, see DKE German Commission for Electrical, Electronic and Information Technologies in DIN and VDE: International Electrotechnical Dictionary IEV entry 311-01-16.
2. ↑ Martin Klein (Ed.): Introduction to the DIN standards. Springer Fachmedien, 12th edition, 1997, p. 788
3. ↑ DIN 55350-13, Terms of Quality Assurance and Statistics - Part 13: Terms for the Accuracy of Determination Procedures and Determination Results , 1987, No. 1.2
4. ↑ Sigmar German, Peter Drath: Manual SI Units: Definition, Realization, Preservation and Distribution of SI Units, Fundamentals of Precision Metrology , Vieweg, 1979, p. 257
5. ↑ Herbert Bernstein: LF and HF measurement technology: measuring with oscilloscopes, network analyzers and spectrum analyzers. , Springer Vieweg, 2015, p. 265
6. ↑ Erwin Meyer, Dieter Guicking: Schwingungslehre. Vieweg. 1974, p. 19
7. ^ Karl-Heinrich Grote, Jörg Feldhusen (Hrsg.): Dubbel: Pocket book for mechanical engineering. Springer, 23rd edition, 2011, p. 29
8. ↑ Horst Germer, Norbert Wefers: measuring electronics: Volume 1 , Hüthig, 1985, p. 41