Talk:Henry (unit)

What is it?

The description does not give any feel for what a Henry measures — Preceding unsigned comment added by 211.30.6.37 (talk) 12:30, 21 February 2006 (UTC)

Henry should be represented as Volt/(Ampere/second) for obvious reasons. It measures the inverse of (d/dt Current)/Voltage. CaffeineWitcher 7:06, 18 March 2020 (UTC)

I agree with the statements above. IMHO I would believe that to the introduction as „ If a current of 1 ampere flowing through a coil produces flux linkage of 1 weber turn, that coil has a self-inductance of 1 henry” I would at least add - if not replace it by - the description according to the definition below „… 1 weber turn, or if a current passing through the coil is changing at a rate of 1 ampere per second induces an emf of 1 volt across the coil, that coil has …“ and so forth. The description as it is now is at the very least confusing. — Preceding unsigned comment added by 2A02:8109:C282:7600:D5B7:32D7:4EDC:F825 (talk) 01:28, 6 January 2025 (UTC)

Meaningless and Unused Units

The equivalent units section is good and informative for dimensional analysis, however, the inclusion of a dimensionaless unit (radians) is meaningless and unable to provide any insight into any physical reality:

$${\begin{alignedat}{6}\mathrm {H} &={\dfrac {\Omega }{\mathrm {rad} {\cdot }\mathrm {Hz} }}&&={\dfrac {\Omega {\cdot }\mathrm {s} }{\mathrm {rad} }}\end{alignedat}}$$

There are many other dimensionless units or combinations of multiple dimesionless units that would equally provide no insights into the underlying physical reality. https://en.wikipedia.org/wiki/Dimensionless_quantity

I can remove if there is no objection. (written Oct 2025) — Preceding unsigned comment added by 210.54.34.142 (talk) 18:15, 9 October 2025 (UTC)

Plural

Is it henrys or henries? —Keenan Pepper 01:56, 17 March 2006 (UTC)

See Talk:Inductance. We seem to have a slight preference for henries, but it's not conclusive. --Heron 18:07, 17 March 2006 (UTC)

Shouldn't this page be renamed to Henry (unit) ?

Yes, it should! Melchoir 10:45, 2 June 2006 (UTC)

Agree - --Rehnn83 11:11, 20 October 2006 (UTC)

Done Steevven1 ^{(Talk) (Contribs) (Gallery)} 00:07, 27 May 2007 (UTC)

Why is there a list of multiples? Aren't they just the standard SI prefixes?

It's there so that someone following a link from microhenry or whatever will know why they are here. We used to have a bunch of articles about various prefixed units, but they were mostly removed (except in a few cases with special reasons for keeping them) and changed to redirects to the base unit. These redirects can now be linked to go directly to the section with the table showing what the linked prefixed unit or prefixed unit symbol means. Gene Nygaard (talk) 02:02, 21 November 2007 (UTC)

Verify

This was on the article page, I moved the comment herre RJFJR 19:24, 30 November 2007 (UTC)

Yes, I think the Henry unit should be kg⋅m⋅s−2⋅A−2. When finding the speed of light in a vacuum 1/sqr(ε0μ0) should cancel everything except m/s. 206.223.144.130 (talk) 23:24, 31 May 2025 (UTC)

The unit conversion for newton may be off by m, rather than m^2 below

$H={\dfrac {{\mbox{m}}^{2}\cdot {\mbox{kg}}}{{\mbox{s}}^{2}\cdot {\mbox{A}}^{2}}}={\dfrac {\mbox{Wb}}{\mbox{A}}}={\dfrac {{\mbox{V}}\cdot {\mbox{s}}}{\mbox{A}}}={\dfrac {{\mbox{m}}^{2}\cdot {\mbox{kg}}}{{\mbox{C}}^{2}}}$

Sense of scale

It would be nice to add something to give a sense of scale. For example, include some pictures of some inductors. How physically big are typical 1-henry inductors? What is the typical inductance of a inductor the size of your small toe? How much would a 1-henry inductor cost? What about a milihenry?

173.66.241.122 (talk) 08:41, 7 March 2016 (UTC)

Hard to put "typical" values in because reference weenies will pounce. Physical size depends on current rating and working voltage as much as inductance values. You'd expect "microhenry" values in the tuned circuits of radio-frequency circuits, but the field of a large DC motor might be many henrys. --Wtshymanski (talk) 02:30, 11 March 2016 (UTC)