Talk:Linear amplifier

This article should be deleted

The articles on Amplifier and Electronic amplifier cover all this material in more detail with better context. Brews ohare (talk) 19:43, 9 January 2008 (UTC)

I agree. Adding merge proposal templates. --mcld (talk) 08:34, 21 May 2010 (UTC)

• Oppose. It is out of process to use a merge proposal to achieve an article deletion. If that is really what you want then WP:AfD is the more appropriate venue. I am opposed to such a deletion in any case, this article addresses a specific application of amplifiers which are not covered in detail in those other articles. True, amplifier classes are covered better elsewhere, but that subject is not the essence of this article. There is certainly information in this article that is not found in the others; the historical note on the WLW transmitter for instance. I would also oppose a genuine merge, the target article is not organised by applications (it does cover RF amps, but in a very bitty way strewn throughout the article) and trying to shoehorn it in there would break the narrative of either this article or the target. A better merge target would have been RF power amplifier, that is, if you are really looking to carry out a merge rather than a deletion. SpinningSpark 11:50, 21 May 2010 (UTC)

• I apologise if I made a mistake in protocol. I suppose it is better to say that I don't agree with the OP, then, and am proposing a merge instead! --mcld (talk) 18:37, 24 May 2010 (UTC)

• Merge any useful content to RF power amplifier. The WLW transmitter stuff, being USA-centric, may be better added to the article about the station. - LuckyLouie (talk) 14:41, 21 May 2010 (UTC)

• Merge. After the merge, the RF power amplifier article should reflect that "linear amplifier" is a term-of-art within amateur radio for a linear amplifier in a separate package which can be built or bought separately from, and used with, a transmitter or tranceiver. If anyone in the future writes enough about linear amplifiers (in any sense of the word) the article can always be reestablished. Jc3s5h (talk) 16:32, 21 May 2010 (UTC)

Comment - Linear amplifier is also a term used to describe a form of Op Amp, e.g. an integrated circuit. Maybe you want to rename this "Linear amplifier (radio)"? - LuckyLouie (talk) 19:31, 24 May 2010 (UTC)

• Oppose. The term "linear amplifier" is used by amateurs, CB operators, and others for amplifiers most often used for HF single-sideband transmissions. It falls within both RF power amplifier and electronic amplifier. I oppose the merger with amplifier, but I favor a merge with electronic amplifier (and deletion of RF power amplifier FWIW). There is little material here that is not covered in electronic amplifier. Amplifier is a weaker article at present, and the term "amplifier" is too general, because it should include non-electronic types of amplifier: fluidic, laser, what-have-you. Albany45 (talk) 20:36, 21 May 2010 (UTC)

• Oppose. This article is about one specific type of amplifier while the Amplifier article is a superficial "overview" of all kinds of amplifiers in general. Roger (talk) 14:14, 2 June 2010 (UTC)
• Oppose as per Dodger67. Keep Amplifier as a general level article with a brief mention of "linear amplifier" linking to a fuller explanation. It will become too long and unwieldy if every type of amplifier is fully described within the main article.Lumos3 (talk) 22:24, 24 September 2010 (UTC)

Put me down as Confused! (on second thought). The Article template says the proposition is to merge Linear Amplifier with Amplifier, but the proposition above is "The article should be deleted." Merger is not the same thing as deletion -- or is it? We need to know what we are voting for. I still think a merger with Electronic Amplifier (not deletion, not merger with Amplifier) might be best.--Albany45 (talk) 19:04, 2 June 2010 (UTC)

Me too. I'd rather see it merged. Keeping this as an article about CB/ham use of the term (sourced to what, I don't know) seems a bit narrowly focused to me. - LuckyLouie (talk) 19:11, 2 June 2010 (UTC)

There appears to more support for merging to Electronic amplifier than Amplifier. I have adjusted the merge banners. --Kvng (talk) 23:11, 20 December 2010 (UTC)

• Support a merge to Electronic amplifier. The same topics are covered in the destination article. I presume there is not enough material to support a Non-linear amplifier article so it should all go into Electronic amplifier. --Kvng (talk) 23:34, 20 December 2010 (UTC)

• Reorganise Electronic amplifier and Amplifier articles first, then decide. They are a bit of a mess and adding this material on (RF-specific) power amplifiers will make whichever already-large article more unwieldy. But my preference would be to put it into the RF power amplifier article (which needs improvement in other areas, I see, but I don't think it should be deleted). I am concerned with the way amplifier-related material in Wikipedia is scattered at present.

I think the best approach is to have the Amplifier article present a "taxonomy" of amplifier types, electronic or not, to put things in context e.g. you should see that a common-collector (emitter-follower) stage is a cousin of both common-base and cathode-follower stages, all of which are within the "Single-stage amplifier" subsection of the "Electronic amplifier circuits" section... but don't get bogged down in details, mainly have links to articles like Transistor amplifier#Common-base.

When I say Electronic amplifier is a bit of a mess, what I mean is, for example, there is a lot of text about Doherty amplifiers, but surprisingly little on other important topics; the various ways of classifying electronic amplifiers is, admittedly, a tough job to do justice to but I feel could be done better if the "Types of amplifier" section was reorganised ("Transistor amplifiers" aren't an alternative type to "Power amplifiers"!) and if some bits further down the article were split out rather than large chunks merged in (especially Classes - which is covered in many other places, including Linear amplifier - and too much emphasis gets placed on what is really the "class of service" of some of the output transistors or valves in defining the type of amplifier when there are choices like "ultra-linear" "quasi-complementary", and so on that deserve as much text).

These are the questions that I think should be considered in deciding on the organisation of amplifier material:

• • can I get to related material easily and clearly when I know my way round the topic (i.e. the expert reader/encyclopaedia-writer's approach)?

• • will someone with less technical knowledge, that is only interested in a particular angle (e.g. distortion in Class AB MOSFET power amplifiers) be able to find what they want without being put off wading through too much irrelevant or over-their-head material?

• • related to that, there is a clear difference between going into all this material from the point of view of the circuitry within (in which case concepts like CMRR will be important), or from the "consumer" view of what the resulting specifications and history, etc are. Shouldn't the job of the Electronic amplifier article must include a springboard to get to the likes of "Quad 405" amplifier (without the reader knowing whether it is valve or transistor, power amp or preamp), e.g. by a section "Commercial amplifiers" and a link to the Quad Electroacoustics article with just a little bit of comment?

Maitchy (talk) 02:30, 4 June 2011 (UTC)

Comment The articles are not going to go exactly to where I envision they should with your approach but I encourage you (and all other editors) to hop in and start making WP:BOLD improvements as you see fit. --Kvng (talk) 16:06, 5 June 2011 (UTC)

• • I agree, either delete, merge, or seriously change is misleading article. It gives the impression that linear amplifiers are used chiefly for amateur radio, which is an EXTREMELY tiny niche of RF communications in general. The frequent mentions of vacuum tubes made me laugh. A linear amplifier is an extremely general purpose device and should be described as such. — Preceding unsigned comment added by 2610:148:610:3211:6127:6D80:AAFA:6146 (talk) 17:29, 25 June 2015 (UTC)

Generator Power?

"A side effect of improving the efficiency is that the current drawn from the high voltage supply will vary more as a function of the power input into the amplifier, this can result in unwanted effects such as the output of the HT pack being modulated by the audio modulated RF driven into the amplifier. An extreme example of this has been observed during radio contests where a large linear is used to amplify morse (carrier on/off keying), it has been the case under some conditions that the wildly changing load on the petrol-driven 240 volt 50 Hz generator set has been sufficient to cause the petrol motor to change speed (and supply frequency) as it attempts to maintain its AC output voltage at 240 volts. In short, any person able to hear the petrol engine will then be able to hear the morse.

"A simple cure for this is to always attach a fixed small load such as several light bulbs to the output of the 240 volt AC generator."

This section seems to be off-topic and/or too much of a detail for this article. We do not give construction tips for building linear amps, for example. Should we delete it?--Albany45 (talk) 02:13, 1 August 2011 (UTC)

Part of the first sentence might be OK; yes, delete the rest. Dicklyon (talk) 03:54, 1 August 2011 (UTC)

I agree. Looks like this article was originally written to focus only on a "ham linear" point of view. - LuckyLouie (talk) 18:14, 1 August 2011 (UTC)

"Linear Amplifier" - who uses term?

Is the term "linear amplifier" (as a noun phrase) used much outside amateur radio and allied areas? A quick search turns up zero non-amateur-related references. If this is an Amateur Radio term (mainly), the article should say so. Of course, engineers are quite interested in linearity of amplifiers, but I am not familiar with using "linear amplifier" to designate a class of amplifiers (e.g., class A - AB2 vs class C). Not to be fussy, but every amplifier is non-linear. Linearity is an ideal and a matter of degree. This might be mentioned as well.--Albany45 (talk) 13:36, 4 August 2011 (UTC)

Better lead and introduction needed.

This article is failing to make a clear case as to why linearity is needed, and also when it's not needed. Linear amplifiers (in the radio sense) are described specifically as such, in contrast to a simpler design that isn't linear. As the talk page comments for deletion imply, this needs to be explained. Andy Dingley (talk) 09:45, 17 October 2012 (UTC)

Agree. I have added a tag. -—Kvng 15:00, 20 October 2012 (UTC)

Early large amplifiers

Removing this section, because it's off topic. Some history of linear amplifiers for RF might be more appropriate.

The first large amplifier used in the United States for public domestic radio broadcasting was in operation between 1934 and 1939 at WLW in Cincinnati. It was an experimental amplifier and was driven by the radio station's regular 50 kW transmitter. Not a linear amplifier, it operated in class C with high-level plate modulation. The amplifier required a dedicated 33 kV electrical substation and a large pond complete with fountains for cooling. It operated with a power input of about 750 kW (plus another 400 kW of audio for the modulator) and its output was 500 kW.

The explanation of Class C is likewise off topic, but we'll leave that for another day. The whole article still needs to be rationalized (ie merged) with respect to other RF amplifier topics.--Albany45 (talk) 03:07, 4 December 2012 (UTC)

I agree, it is off topic here. I inserted a copy of it into WLW#History. -—Kvng 19:48, 6 December 2012 (UTC)

"A linear amplifier is an electronic circuit whose output is proportional to its input ..."

Ahhh, more exactly, "A linear amplifier is an electronic circuit whose output will increase linearly in response to a linear imput".

Quasi-mathematically: output = (amplification_constant X input) + base_constant.

Your definition is a subset of this, with base_constant = zero. Old_Wombat (talk) 07:54, 10 June 2013 (UTC)