Should you use the word "transistor" when refering to non-BJT devices? - Page 1
Forum section: electronics / beginners

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: May 01, 2017, 10:57:05 am
content: So, I realize this is something that one can have various opinions about.I also realize that MOSFET, JFET, IGBT, HEMT, ... all are acronyms forSomethingSomething ...Transistor, and that BJT stands for bipolar junction transistorHowever, I don't know if this is common, but I seem to remember that the electronics kits I grew up with would use "transistor" when refering to BJTs, and "MOSFET" when refering to MOSFETs (obviously). This distinction stuck with me, and thus in general, when people say "transistor" what I hear in my head is "BJT", especially if we are talking about individual devices in a circuit, for example: "Current I1 will turn on transistor M2 (...)". I've seen other books seem to use this "transistor is a synonym for BJT" style, although I can't come up with any specific titles right now.Hence, I would like to ask a)Is this actually a common thing, or have I just had a bad set of samples?Is it a good habit to avoid using "transistor" to refer to JFET/MOSFET/... and instead call them by their more specific name? Should I do this for BJTs as well?

author: danadak
author_rank: Super Contributor
timestamp: May 01, 2017, 11:36:51 am
content: Seems like Wiki defines it for multiple types. For examplethere were Tetrode transistors back in the day, 4 leadsvs 3, multiple base or collector or emitter leads. Point beingthey were also considered to be transistors.https://en.wikipedia.org/wiki/Transistorhttps://en.wikipedia.org/wiki/Tetrode_transistorRegards, Dana.

author: madires
author_rank: Super Contributor
timestamp: May 01, 2017, 11:55:24 am
content: Same here, the term transistor usually refers to a BJT since it's the most common type.

author: VEGETA
author_rank: Super Contributor
timestamp: May 01, 2017, 12:28:13 pm
content: well, as you said, MOSFETs are transistors by definition but generally people used to say "transistor" to a BJT and somehow it stuck with it.

author: Zero999
author_rank: Super Contributor
timestamp: May 01, 2017, 05:07:50 pm
content: It's most likely because the BJT is usually the first type of transistor people learn about.To answer the original question: yes, it's correct to use the term "transistor" to refer to other transistors than BJTs, such as JFETs, MOSFETs, UJTs etc.Also note that most people will probably think of an NPN device, rather than PNP when someone talks about a transistor.Personally, it depends on the context. If it's a CMOS circuit, then I know they're all MOSFETs, not BJTs.

author: rfeecs
author_rank: Frequent Contributor
timestamp: May 01, 2017, 05:27:31 pm
content: Quote from: TheUnnamedNewbie on May 01, 2017, 10:57:05 amI seems to be only a thing with beginners and hobbyists?Transistor is the general term. BJT, MOSFET, HBT, HEMT are specific. I would avoid saying "MOSFET transistor" or "BJT transistor".Interesting that SCRs, TRIACs, etc. are not called transistors. They would seem to qualify. Perhaps because they function like switches instead of linear amplifiers?

author: james_s
author_rank: Super Contributor
timestamp: May 01, 2017, 06:03:26 pm
content: I think it's acceptable to call a mosfet a "transistor" because it's a type of transistor, although normally if I just say "transistor" I'm referring to a BJT as they're the "ordinary" type of transistor.SCRs and Triacs are a subset of Thyristor.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: May 01, 2017, 06:09:05 pm
content: It seems like I might not have been clear enough in my original post.I am aware that it is correct to refer to any of the listed devices (MOSFET and what not) as a "transistor", as this is what it is. However, what I was wondering is if it is a good idea to avoid using transistor when refering to anything other than BJTs, except when it's really obvious (like when discussing a CMOS circuit), in order to avoid confusion.I ask this because when I read the title of a paper that goes say "A novel 6 transistor gain-boosted cascode topology" I will immediately assume the paper is dealing with BJTs. I can imagine that if many others do this as well, it could be a good idea to just directly specify what you are talking about. This way, you would avoid people getting confused about whats going on.

author: rfeecs
author_rank: Frequent Contributor
timestamp: May 01, 2017, 06:24:41 pm
content: Quote from: TheUnnamedNewbie on May 01, 2017, 06:09:05 pmI think few people would interpret that title automatically as referring to BJT. Cascode is very common in CMOS as well.At least in industry and academia, people just do not assume transistor means BJT.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 01, 2017, 06:40:00 pm
content: Quote from: TheUnnamedNewbie on May 01, 2017, 06:09:05 pmDepends on context -- as language usually does.For example,Iwill assume the paper is talking about MOSFETs, in a CMOS or III-V process, because I know almost no one uses BJTs anymore. HBTs maybe, but those are unusual enough that they'll probably specify in the title or abstract.OTOH, an historical paper (say 70s or earlier) may be talking about BJTs.Tim

author: Ratch
author_rank: Regular Contributor
timestamp: May 01, 2017, 06:46:52 pm
content: Quote from: TheUnnamedNewbie on May 01, 2017, 10:57:05 amSince the last letter of the acronyms you listed means "transistor", anytime you use "transistor", it could mean any of those acronyms. The particular type of transistor is determined by context and commonality. Just like "car" can mean Chevy, Ford, Honda, etc.Ratch

author: MagicSmoker
author_rank: Super Contributor
timestamp: May 01, 2017, 06:52:54 pm
content: Quote from: rfeecs on May 01, 2017, 05:27:31 pmA transistor is a 3-terminal device in which the control terminal can continuously affect the flow of current through the other two terminals.Thyristors don't qualify as transistors because their control terminal loses the ability to control the flow of current once it has turned the device on. External circuit conditions must be set up to turn a thyristor off (called commutation).And as others have mentioned already, transistor is a general term whereas BJT, IGBT, JFET, MOSFET, etc., describe specific types of transistors.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: May 01, 2017, 06:56:30 pm
content: As I have stated before, twice, and will state again: I know that all of them are transistors, and that transistor is the general term. However, I've also seen transistor been used to discribe BJTs specificly. I wondered if others had seen the same, and what the thoughts were about this.

author: rfeecs
author_rank: Frequent Contributor
timestamp: May 01, 2017, 07:03:38 pm
content: Quote from: MagicSmoker on May 01, 2017, 06:52:54 pmThat's what I figured. Wikipedia's Thyristor page says about the same thing:QuoteIt also mentions the origin of the name:Quote

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: May 01, 2017, 07:06:02 pm
content: Quote from: MagicSmoker on May 01, 2017, 06:52:54 pmThe 3 terminal part is not required. A MOSFET, for example, is a 4-terminal device.

author: rfeecs
author_rank: Frequent Contributor
timestamp: May 01, 2017, 07:09:13 pm
content: Quote from: TheUnnamedNewbie on May 01, 2017, 07:06:02 pmWe can argue about definitions forever. That definition also would apply to a vacuum tube triode. Unless you count the heater terminals.

author: MagicSmoker
author_rank: Super Contributor
timestamp: May 01, 2017, 08:41:48 pm
content: Quote from: TheUnnamedNewbie on May 01, 2017, 06:56:30 pmYes, I often use the word transistor to refer to a BJT, specifically. Its not something I worry overly much about. However, I rarely use FET to refer to MOSFETs specifically, as for some reason I feel compelled to always make a distinction between a JFET and a MOSFET.

author: Zero999
author_rank: Super Contributor
timestamp: May 01, 2017, 10:11:20 pm
content: Quote from: TheUnnamedNewbie on May 01, 2017, 06:56:30 pmI don't believe I've seen such a thing personally, unless it was reading some posts here, in the beginners section.Can you post any links to where you have encountered this?

author: Bud
author_rank: Super Contributor
timestamp: May 02, 2017, 12:07:10 am
content: Quote from: Hero999 on May 01, 2017, 05:07:50 pmWhat??!

author: amspire
author_rank: Super Contributor
timestamp: May 02, 2017, 12:56:02 am
content: Just choose your use of terms for the clearest communication. If you just say the word "transistor", many people will think of a bipolar junction transistor. If that is a problem in the idea you are trying to communicate, use terms like MOSFET, JFET, etc instead.If you are communicating with non-electronics people, often just calling all the devices "transistor" is fine. That is a word that means more to them then HEMT or IGBT.In a parts list, it is fine listing different types of transistors under the heading "Transistor".If you are communicating with a semi-technical audience, it is always a good idea to define the abbreviations on the first use - "junction field effect transistor (JFET)". Don't force people to have to google terms just to work out what you are saying.

author: jolshefsky
author_rank: Regular Contributor
timestamp: May 02, 2017, 01:12:09 am
content: The pedant in me cringes at "BJT transistor" and "FET transistor" since the expanded acronyms would make them "bipolar-junction transistor transistor" and "field-effect transistor transistor."My own experience-based definition says a transistor is a simple (e.g. not an op-amp) semiconductor-based device (e.g. silicon) that performs an amplification function. And since BJTs and FETs are all transistors, saying "transistor" is ambiguous and could refer to any of them.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 02, 2017, 04:14:30 am
content: Yeah, you don't need to redundantly say "transistor" if you've already specified that you're using (MOS)FETs or BJTs or whatever.Just say one of those, if you're being specific. The acronym can then be defined/specified, or left to the reader to figure out (by asking, or, preferably, by JFGI).Tim

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: May 02, 2017, 05:23:47 am
content: Quote from: T3sl4co1l on May 02, 2017, 04:14:30 amGot to tell people that I'm using a BJT transistor to power the LCD display in my ATM machine tho!Jokes aside:Interesting that some people are very surprised about this being a thing, where as others confirm seeing the same. Perhaps it's something very common in hobby circles that trickles down into engineering people as the go the university?

author: Zero999
author_rank: Super Contributor
timestamp: May 02, 2017, 07:39:16 am
content: Quote from: jolshefsky on May 02, 2017, 01:12:09 amThat seems to be common in English speaking countries. PIN number, ATM machine, PAT testing, etc.