Talk:Bipolar transistor biasing
![]() | This article is rated Start-class on Wikipedia's content assessment scale. It is of interest to the following WikiProjects: | ||||||||||
|
|
![]() | This article links to one or more target anchors that no longer exist.
Please help fix the broken anchors. You can remove this template after fixing the problems. | Reporting errors |
Peer Review
[edit]I'd like to request any editor whos had a look at this page to please go to the peer review link above and add your suggestions to improve the article. Thanks, xC | ☎ 19:28, 2 November 2007 (UTC)
Learn to talk
[edit]"... Q-point, is the point on the output characteristics that shows the DC collector–emitter voltage (Vce) and the collector current (Ic) with no input signal applied." What on EARTH does 'shows' mean??? Totally meaningless sentence.
Auto Peer Review
[edit]The following suggestions were generated by a semi-automatic javascript program, and might not be applicable for the article in question.
- Please expand the lead to conform with guidelines at Wikipedia:Lead. The article should have an appropriate number of paragraphs as is shown on WP:LEAD, and should adequately summarize the article.[?]
- Consider adding more links to the article; per Wikipedia:Manual of Style (links) and Wikipedia:Build the web, create links to relevant articles.[?]
- If there is not a free use image in the top right corner of the article, please try to find and include one.[?]
- There may be an applicable infobox for this article. For example, see Template:Infobox Person, Template:Infobox School, or Template:Infobox City.[?] (Note that there might not be an applicable infobox; remember that these suggestions are not generated manually)
- Please reorder/rename the last few sections to follow guidelines at Wikipedia:Guide to layout.[?]
- There are a few occurrences of weasel words in this article- please observe WP:AWT. Certain phrases should specify exactly who supports, considers, believes, etc., such a view.
- This article needs footnotes, preferably in the cite.php format recommended by WP:WIAFA. Simply, enclose inline citations, with WP:CITE or WP:CITE/ES information, with <ref>THE FOOTNOTE</ref>. At the bottom of the article, in a section named “References” or “Footnotes”, add
<div class="references-small"><references/></div>
.[?] - Please ensure that the article has gone through a thorough copyediting so that it exemplifies some of Wikipedia's best work. See also User:Tony1/How to satisfy Criterion 1a.[?]
You may wish to browse through User:AndyZ/Suggestions for further ideas. Thanks, xC | ☎ 19:30, 2 November 2007 (UTC)
External links modified
[edit]Hello fellow Wikipedians,
I have just modified one external link on Bipolar transistor biasing. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
- Added archive https://web.archive.org/web/20071125125418/http://www.tpub.com:80/neets/book7/25d.htm to http://www.tpub.com/neets/book7/25d.htm
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{Sourcecheck}}
).
This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template {{source check}}
(last update: 5 June 2024).
- If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
- If you found an error with any archives or the URLs themselves, you can fix them with this tool.
Cheers.—InternetArchiveBot (Report bug) 00:50, 3 November 2016 (UTC)
Practical amplifier circuit may not work
[edit]The practical amplifier circuit may not work for two reasons.
The first, alluded to in the article, is that the output transistors may go into thermal runaway. It would be good if the articled showed the rigorous way to calculate the minimum resistance needed. I'm doing this on the top of my head but the constraint should look like VCE*gm/(1+gm*Rdegen)*(2.2mV/degC)*ThetaJA < 1. That is, an increment in power causes a temperature change proportional to ThetaJA. This in turn causes a decrease in the VBE needed for fixed bias - by approximately 2.2mV/degC. Multiplication by the effective transconductance, gm/(1+gm*Rdegen), then provides the change in collector current. This is turn causes a change in power proportional to VCE. Rdegen should be chosen so that in the worst case, the thermal/power feedback is less than 1.
As regards the 2.2mV/degC...this confuses a lot of people. If one simply takes the derivative of the equation Ic=Is*exp(q*Vbe/(k*T)), one would expect the VBE to need to increase with temperature for a fixed current bias. However, Is also has a temperature dependence and this more than compensates for the T in the exponential.
The second issue why the circuit may not work is that it is not compensated. There should be a capacitive feedback from the output to the input of the common-emitter (PNP) stage. This is known as Miller compensation. On top of that, the emitter followers may oscillate - especially driving capacitive loads. This is covered in Gray & Meyer, a standard textbook on circuit design; it's relatively easy to derive too. ArtKalb (talk) 21:21, 26 July 2022 (UTC)
- Wikipedia is not a textbook. The amplifier might also have terrible impedance mismatch and low gain at 22 GHz. Notice the article title. --Wtshymanski (talk) 02:18, 14 August 2022 (UTC)