different between impedance vs resistivity

English

Etymology

impede +? -ance. Physics usage: coined by Oliver Heaviside in 1886.

Pronunciation

• (Received Pronunciation) IPA^(key): /?m?pi?dn?s/

Noun

impedance (countable and uncountable, plural impedances)

1. The act of impeding; that which impedes; a hindrance.
   • 2012, R. Crafton Gibbs, Spirit Growth: Logos 2, Vol. 2, of Writing God's Book of Life (page 31)

     Faithful yielding is therefore a display of love before God by preparing to respond to his Call to Arms, even though He may not send us into the front lines of battle if some disability or impedance of Satan prevents us from action […]

2. (physics) A measure of the opposition to the flow of an alternating current in a circuit; the aggregation of its resistance, and inductive and capacitive reactances; the ratio of voltage to current treated as complex quantities.
3. (physics) A quantity analogous to electrical impedance in some other energy domain
   1. (physics, usually with “mechanical”) a measure of opposition to motion of something subjected to a force; the ratio of force to velocity treated as complex quantities.
   2. (physics, usually with “acoustic” or “sound”) the ratio of sound pressure to volume flow rate treated as complex quantities.
4. (by analogy, software engineering, usually with “mismatch”) a measure of the opposition caused by differences between two paradigms, especially between object-oriented development and relational databases
   • 1997, Bhavani M. Thuraisingham, Data Management Systems: Evolution and Interoperation ?ISBN, CRC Press, page 33:

     Some argue that having impedance mismatch is difficult for programming intensive applications.

   • 2002, Jim Melton, Advanced SQL:1999: Understanding Object-Relational and Other Advanced Features ?ISBN, Morgan Kaufmann, page 353:

     But the impedance mismatch between SQL and Java was no better than between SQL and other languages.

   • 2004, Scott W. Ambler, The Object Primer: Agile Model-Driven Development with UML 2.0 ?ISBN, Cambridge University Press, page 442:

     Why does a technological impedance mismatch exist?

Usage notes

Impedance is universally given the symbol Z in technical works which is often used as a synonym for the word even in running text.

Derived terms

Related terms

• impediment

Translations

English

Etymology

resistive +? -ity

Noun

resistivity (countable and uncountable, plural resistivities)

1. (electricity) The resistance offered at a particular temperature by an electrical conductor of any given material in a cube of unit length, expressed in ohm-metres (?m) in the metric system of measurement.
2. (thermodynamics) The reciprocal of thermal conductivity, having SI unit: m K W^-1

Derived terms

Translations

References

• William Dwight Whitney and Benjamin E[li] Smith, editors (1914) , “resistance”, in The Century Dictionary: An Encyclopedic Lexicon of the English Language, volume IV (P–Simulant), revised edition, New York, N.Y.: The Century Co., OCLC 1078064371, page 5105.
• Ingo W. D. Hackh (1929) A Chemical Dictionary : Containing the Words Generally Used in Chemistry, and Many of the Terms Used in the Related Sciences … Based on Recent Chemical Literature, P. Blakiston's Son, entry “specific”, page 678