Talk:JFET

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       I_{DS} = I_{DSS}\left[1 + \frac{V_{GS}}{V_P}\right]^2 ?????? Is this right??? in the german wikipedia you can read         I_{DS} = I_{DSS}\left[1 - \frac{V_{GS}}{V_P}\right]^2 minus in placace of plus  —Preceding unsigned comment added by 89.49.121.34 (talk) 11:06, 6 March 2008 (UTC)

Contents

[edit] Comparison with other transistors

This section should describe in concrete terms why a JFET would be used and not a MOSFET. We see some functional differences but not generalization. Give me funtions. ~


[edit] Split

splitup of article Field effect transistor in progress, please see Talk:Field effect transistor Pjacobi 15:52, 19 Jul 2004 (UTC)

  • Done Pjacobi 21:28, 19 Jul 2004 (UTC)

[edit] Too technical

The language in this article is probably too technical for most Wikipedians. It needs a good copyedit. I've just linked everything I could; some technical terms are still unlinked. - dcljr 18:41, 16 Sep 2004 (UTC)

In particular, VP in the equations needs to be defined. 71.41.210.146 12:04, 30 October 2007 (UTC)

[edit] Merge - Uses of jfet

It has been suggested that Uses of jfet be merged into this article or section.

User:Ywywyw (Contributions) did not say why they put it in a separate article.

User:Yume no Kishi proposed that it be merged into JFET

Support It should just be a heading. --RobBrisbane 11:01, 8 July 2007 (UTC)

merge it!!XU-engineer 18:25, 29 July 2007 (UTC)

I don't even think it's worth attempting to merge; it appears to have been created by cutting phrases from descriptions of specific circuits and pasting them together without context. Maybe it was even created by a bot? Delete. --Theodore Kloba 12:17, 20 October 2007 (UTC)

Not to mention that at least some of the material is subject to copyright issues. I've deleted the page and replaced it with a redirect instead. --Michael Snow 20:22, 9 November 2007 (UTC)

[edit] Error?

I have a textbook in front of me that says current in n-type JFETs flows from drain to source. —Preceding unsigned comment added by 199.106.52.17 (talk) 16:18, 30 October 2007 (UTC)

That's definitely true of power MOSFETs. In an N-channel current flows from drain to source (electrons flow from source to drain), In a P-channel current flows from source to drain (electrons flow from drain to source). The reason for this is relatively obvious if you consider that in both cases the source is connected to the bulk, yet they have the N and P doped silicon reversed. I don't see any reason why JFETs would be any different. I believe that signal MOSFETs inside ICs (and possibly some monolothic FETs, although I am not sure) do not have the source connect to the bulk, so current flow can be bidirectional. Therefore, it's a bit hard to generalise. But I think the fault in the article is that it is not very specific. The statement made is true, for one common type of JFET (P-channel), but not the other major type. N-channel is probably more common, in fact. Last time I bought JFETs I don't even remember the store offering P-channels. I would qualify the statement. —Preceding unsigned comment added by 220.233.81.49 (talk) 17:26, 4 January 2008 (UTC)

[edit] Disjointed style

The first paragraph of the "comparison with other transistors" is bizarrely structured. It says (paraphrased) "x is small. y is extremely small. x is much smaller than z".

Wouldn't it be clearer to say "JFET have much smaller gate currents than BJT, making higher input impedances possible. MOSFET have even smaller gate currents but JFETs have higher transconductance (explain why this is desirable)." —Preceding unsigned comment added by 213.41.173.68 (talk) 22:23, 17 November 2007 (UTC)

[edit] Unclear

The article mentions negative VGS. While this may be perfectly clear to EE, it is not stated whether VAB means potential of A minus potential of B or the reverse.

People who are learning this stuff will benefit from an explanatory sentence like "i.e. the gate is at a lower/higher potential than the source". —Preceding unsigned comment added by 213.41.173.68 (talk) 22:30, 17 November 2007 (UTC)

[edit] Function

Besides comparing the JFET with a garden hose this section explains nothing at all. I'm not into this myself currently, but explaining (physically) what happens when gate voltage changes would be the least imho. --87.185.10.163 (talk) 20:44, 13 December 2007 (UTC)

A picture of the junctions in different states would be nice? I also think a picture of just the physical layout of various types of FETs would be useful. This information is typically available at simiconductor manufacturer's websites.
I guess I'll try to make some.

JWhiteheadcc (talk) 09:02, 2 April 2008 (UTC)