Henry (unit)
Physical unit | |
---|---|
Unit name | Henry |
Unit symbol | |
Physical quantity (s) | Inductance |
Formula symbol | |
dimension | |
system | International system of units |
In SI units | |
Named after | Joseph Henry |
Derived from | Volts , seconds , amps |
Henry is the unit of inductance in the SI system of units and is named after Joseph Henry . It is specific to each conductor coil and is usually indicated on it.
A coil has an inductance of 1 henry if a self-induction voltage of 1 volt is produced with a uniform current change of 1 ampere in 1 second .
CGS system of units
The Abhenry (abH) is the outdated unit of measurement for inductance from the electromagnetic CGS system of units . It applies
- 1 abH = 10 ^{−9} H = 1 nH (nanohenry)
In an inductance of 1 abH, a current increasing by 1 Abampere per second generates a voltage of 1 Abvolt .
The stathenry (statH) is the outdated unit of measure for inductance from the electrostatic CGS system of units . It applies
- 1 statH = c^{ 2} · 10 ^{−5} H ≈ 8.98755 · 10 ^{11} H ≈ 899 GH (Gigahenry)
In an inductance of 1 Stath to a 1 generates Statampere increasing per second current is a voltage of 1 statvolt .
history
Before the introduction of the SI , today's SI Henry was referred to as the absolute Henry , while the Henry , which was derived from the definition of the (international) ohm at that time, was called the international Henry . Since the national standard authorities had determined different conversion factors based on the measurement regulations of the definitions, there were nationally different numerical values for the international Henry. The International Committee for Weights and Measures put 1946 firmly the average international ohms with 1.00049 Ω, which also applies:
- 1 medium international henry = 1 H _{int} = 1,00049 H
The American international Henry was also significant:
- 1 U.S. International Henry = 1,000495 H.
The Henry was formerly also known as the quadrant , since 1 Henry also corresponds to the dimension according to the length of an earth quadrant of 10 ^{9} cm.
See also
Sources and individual references
- Peter Kurzweil: The Vieweg unit lexicon: formulas and terms from physics, chemistry and technology . Springer-Verlag, March 9, 2013, ISBN 978-3-322-92920-4 , p. 152.
- ^ Electrical Engineers Handbook Electric Power , Harold Pender, William A. Del Mar, 1949, pp. 1-39.
- ^ Gustav Benischke: The scientific foundations of electrical engineering , Springer-Verlag, Berlin / Heidelberg, 1907, p. 570.