Talk:Space charge

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Physics Low‑importance

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Electronics Low‑importance

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Comments

We need to disambiguate EMF, but I'm not into EE encough to know in this case whether it should point to electromagnetic field or Electromotive force. Someone please help. -Anthropos 13:06, 20 Dec 2003 (UTC)

It appears from the context that it should point to electromotive force, so I've changed it from the automated disambiguation.

Also, I've wikified Krishnavedala's contributions a bit. I've unlinked Image:Childlaw.JPG, which seems to me that it should be removed; I have no idea how to go about this. I think I've translated it to TeX properly, but the image was rather ambiguous. I can't say anything on the accuracy or relevance of what Krishnavedala has added; I'm only a sophomore physics major looking for stuff to clean up. If anyone can improve this section, please do so. 24.118.220.84 02:10, 9 Jun 2005 (UTC)

--
Krishnavedala image Childlaw.JPG
ChildLangmuirLawGraph1.svg
"I can't say anything on the accuracy or relevance of what Krishnavedala has added"
As far as I can tell, the Child's Law image ChildLangmuirLawGraph1.svg is just wrong. It appears to plot V^3, not V^(3/2) or V^1.5.
Unless somebody objects, I will post a graph of V^1.5.
PRR (talk) 23:10, 19 June 2011 (UTC)[reply]

minor edit

I added definitions of the variables in the equation for Child's law.

  --Geoff

I wonder what the definition for ν is —Preceding unsigned comment added by 71.238.185.224 (talk) 19:25, 12 April 2009 (UTC)[reply]

I cannot find any definition for ν. It is not in Child's original article (Phys. Rev. 32, 492 (1911)). Another paper I (randomly) found (Ang et al, Phys. Plasmas 13 056701 (2006) ) writes Child's Law as:

J={\frac {4\epsilon _{0}}{9}}{\sqrt {2e/m_{e}}}{\frac {V^{3/2}}{D^{2}}}

. Numerically, one finds

{\frac {4\epsilon _{0}}{9}}{\sqrt {2e/m_{e}}}=2.33\times 10^{-6}

, as written in the current article. So I think the

\nu

should be removed, and the numerical prefactor replaced by the relevant physical quantities. Chucklapuck (talk) 19:44, 15 October 2009 (UTC)[reply]

Mott's (?) steady-state space-charge-limited conduction

It is clear that the relation given in the section 'Mott's limited steady-state..' has anything to do with Mott? Can anyone give a reference for this? This expression already appeared in early papers by Shockley (see e.g. W. Shockley and R. C. Prim, Phys. Rev. 90, 753 - 758 (1953), Eq.(1.13)). Chucklapuck (talk) 19:44, 15 October 2009 (UTC)[reply]

It is also known as Mott-Gurney-Law $j\propto U^{2}$ (Space-charge Limited Current, SCLC). Hear the Cilds-Law $j\propto U^{1.5}$ is refered to as SCLC? But isn't SCLC $j\propto U^{2}$ ? Makes no sense... —Preceding unsigned comment added by 77.176.79.30 (talk) 16:14, 22 August 2010 (UTC)[reply]

what about non-high-vacuum?

"If the "vacuum" has a pressure of 10-6 mmHg or less, the main vehicle of conduction is electrons." this exposes only high vacuum conditions. what if I have a plasma within a gas at a pressure of, say, 15 to 40 torr? —Preceding unsigned comment added by 99.233.186.4 (talk) 06:20, 24 November 2010 (UTC)[reply]

Incorrect graph

Thank you for pointing out the error. The graph of Child's Law is now rectified. --ElectroKid 17:23, 22 June 2011 (UTC) — Preceding unsigned comment added by Krishnavedala (talk • contribs)