Talk:JFET

message: There is a real mismatch with spanish version. There, you can read I_D =  \frac{k}{2}V_{DS}(V_{GS} - V_p) instead of I_D = (2a) \frac{W}{L} q N_d {{\mu}_n} \left[1 - \sqrt{\frac{V_{GS}}{V_P}}\right]V_{DS} for the current in the linear region.
Does anybody know which is the correct expression?.  —Preceding unsigned comment added by Aasdelat (talk • contribs) 15:19, 6 August 2008 (UTC)
thread_title: Spanish Version

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

message: 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)
replies: text: In particular, VP in the equations needs to be defined.  71.41.210.146 12:04, 30 October 2007 (UTC)
thread_title:  Too technical 

message: 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)
replies: text: 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)
thread_title:  Merge - Uses of JFETs 

message: 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)
replies: text: 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)
thread_title:  Error? 

message: 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)
thread_title:  Disjointed style 

message: On the 'Mathematical model' part it's not clear what Id, Ids and Idss are.--CaioMarcos (talk) 04:48, 14 July 2008 (UTC)
thread_title:  Mathematical model 

message: The sections "Schematic symbols" and "Comparison with other transistors" of the 13:32, 13 January 2009 BorgQueen version of this article are translated in to Chinese Wikipedia--Wing (talk) 15:10, 6 February 2009 (UTC)
thread_title:  Translation into Chinese Wikipedia 

message: The phrase "for the Temic J201 device" seems overtly advert-like. Perhaps this could be changed to something a bit more generic?  — Preceding unsigned comment added by 173.74.164.193 (talk) 03:55, 14 October 2011 (UTC)
thread_title:  Advertising 

message: I know that many people (especially technically apt) use only the term "JFET".
But for the average Wikipedia reader the full name is more understandable.
Abbreviated references to the article will then display the full name of the device (as a tool-tip and/or in the status-bar) when hovered,
like here for example: FET
I believe spelling out the title would be closer to the  Manual of Style and the  title format recommendations.
These recommend only abbreviations like LASER (Light Amplification by Stimulated Emission of Radiation) to stay abbreviated even in the page title.
After the move  double redirects must be cleaned up, of course.
But there are even some bots to do that job.
What do you think?  Zeptomoon chat/chase 11:16, 14 October 2012 (UTC)
replies: text: Well, In my experience, JFET is very similar to laser. When you study microelectronics, it's presented to you about once what the letters stand for and after that its not mentioned again. You just call it a JFET (or Laser). --71.38.170.27 (talk) 05:22, 14 November 2012 (UTC)
thread_title:  Let's expand the abbreviation in the title 

message: In this 2008 edit, the craziness started by relabeling the small-voltage IDS as IDSS, which later got called a saturation current, since that's what that wrong name would usually mean.  The model is all wrong.  If we had a source we could go back and look and fix it.  Maybe someone with a source handy will try to make it right.  Dicklyon (talk) 02:11, 9 February 2014 (UTC)
thread_title:  Mathematic model fracked 

message: A section is needed for the relatively new SiC JFETs. Anybody? --Theodore Kloba (talk) 15:50, 13 March 2015 (UTC)
thread_title:  [[Silicon Carbide]] JFETs 

message: Towards the end of the introduction part, its written that in a n channel jfet , the voltage applied at the gate is lower than that applied at the source, and vice-versa for p channel. Lower voltage applied implies lower potential right? (So that GS junction can be reverse biased) . So could I change it to say that as that is more simpler to understand.. Mr.Mog (talk) 05:30, 2 March 2019 (UTC)
replies: text: Yes, pretty much so.  The lead image caption is also needing work; it says "Electric current from source to drain in a p-channel JFET is restricted when a voltage is applied to the gate."  But "when a voltage is applied" is meaningless.  Should say perhaps "when a voltage that reverse biases the gate junction is applied".  Also note that it's actually possible, though not typical, to have an "enhancement mode" JFET, which is "off" at zero bias and turns on with forward bias (up to about 0.5 V). Dicklyon (talk) 07:04, 2 March 2019 (UTC)
thread_title:  Meaning of higher voltage at the end of the introduction 

message: No wonder I've always been confused about this.  I've found references that define the terms to mean completely different things:
* Threshold voltage:
** value of vGS .. for which the channel is completely depleted .. vGS=VGS(OFF).
** the gate-source voltage at which drain current approaches zero
* Cutoff voltage
** the gate-source voltage at which drain current approaches zero .. VGS(OFF)
** VGS (off). It is the gate-source voltage where the channel is completely cut off and the drain current becomes zero.
** VGS(off) is the value of VGS at which the drain current is 0.
** https://www.researchgate.net/profile/Daniel_Montes3/publication/303945767/figure/fig21/AS:743982732673026@1554390714177/MOSFET-Behavior-Showing-Drain-Current-vs-Vds-with-Various-Vgs-in-Ohmic-and-Saturation_Q640.jpg VGS(off) is horizontal line at bottom
* Pinch-off voltage definition 1:
** value of vGS .. for which the channel is completely depleted .. vGS=VGS(OFF)
** At this value of vGS the channel is completely depleted .. denoted VP
** the gate-source voltage at which drain current approaches zero .. VP
* Pinch-off voltage definition 2:
** (VP). It is the minimum drain-source voltage at which the drain current essentially becomes constant.
** This is a vertical line on the IDS vs VDS graph.
** https://nanopdf.com/download/8-chapter-7_pdf shows this vertical Vp line, but also labels another line as "pinch off" for another VGS
** https://www.electronics-tutorials.ws/wp-content/uploads/2018/05/transistor-tran18.gif shows VP as a vertical line on VDS axis, but also shows "Pinch-off Region" at the bottom
** http://elektroarsenal.net/img/720/image841_0.jpg VDS(sat) is a curved line, defined in relation to VP which is a vertical line.
** https://www.researchgate.net/profile/Daniel_Montes3/publication/303945767/figure/fig21/AS:743982732673026@1554390714177/MOSFET-Behavior-Showing-Drain-Current-vs-Vds-with-Various-Vgs-in-Ohmic-and-Saturation_Q640.jpg Vertical line Vp
* Pinch-off voltage definition 3:
** VP is the value of the VDS at which the drain current reaches a constant value for a given value of VGS.
*** "for a given VGS" means it follows the curve (and is better known as VDS(sat)?)
** https://www.tina.com/resources/home/field-effect-transistor-amplifiers-2/3-large-signal-equivalent-circuit/#attachment_1916 has "pinchoff voltages" along a curved line
We should not be using the term "pinch-off voltage", then, except for definition 2 (unless there's an unambiguous alternative for that). — Omegatron (talk) 02:45, 4 January 2021 (UTC)
thread_title:  Pinch-off voltage 

message: Hi,
Could someone add a “Usage” or “Applications” section that concisely summarizes JFETs’ most common industrial usage and/or the most common commercial applications wherefor JFETs are used?  For example, were JFETs ever used for digital logic, or did solid-state digital logic jump directly from primarily using BJTs directly to primarily using MOSFETs as the implementation technology?  ’preciate it  —Arrandale Westmere (talk) 03:34, 22 October 2023 (UTC)
replies: text: It's funny I've never heard of JFETs being used for digital logic.  But I googled, and sure enough found there is at least one application for JFET SiC digital logic cause it can operate at over 500 degrees Celsius with radiation, apparently (https://www.techbriefs.com/component/content/article/tb/pub/briefs/semiconductors-and-ics/3415). Em3rgent0rdr (talk) 03:50, 22 October 2023 (UTC)
thread_title: Usage