Does PNP saturate more readily and Heavily than NPN? - Page 1
Forum section: electronics / beginners

author: Faringdon
author_rank: Super Contributor
timestamp: November 09, 2023, 08:25:14 pm
content: HiDoes PNP saturate more readily and heavily than NPN?eg 2N3904/2N3906..the '3904 has lower Vsat and i suspect that this means it goes more deeply into saturation (more minority carriers astray) than '3906?2N3904 NPNhttps://www.onsemi.com/pdf/datasheet/2n3906-d.pdf2N3906 PNPhttps://www.onsemi.com/pdf/datasheet/2n3903-d.pdf

author: SuzyC
author_rank: Frequent Contributor
timestamp: November 09, 2023, 11:51:58 pm
content: No, you say so yourself in your initial post about the Vsat specs for the 3904 NPN

author: tggzzz
author_rank: Super Contributor
timestamp: November 09, 2023, 11:59:50 pm
content: Quote from: SuzyC on November 09, 2023, 11:51:58 pmThis is another faringdon/treez question, and as usual it should be ignored.Why? See the example below, note the lack of supporting context. Expect to find it emitted in either subsequent posts, or in a different thread that is almost a double post.Here's one other recent example..Quote from: tggzzz on November 07, 2023, 09:50:19 pm

author: Faringdon
author_rank: Super Contributor
timestamp: November 10, 2023, 06:46:38 am
content: QuoteThanks, as such, does a lower saturation voltage mean "less saturated"?

author: Faringdon
author_rank: Super Contributor
timestamp: November 10, 2023, 07:24:29 am
content: QuoteThanks tggzzz!....i know exactly where youre coming from…I once had two PhD electronics guys put with me, and the gaffer was telling them to strip all the knowledge out of my brain and put it into theirs! They were machine gunning me with questions such that I couldn’t actually do my own work…I was their slave, and the gaffer required this….they weren’t that great…one didn’t know what a relay was. We had to mod up some badly designed SMPS's for a visit by a big (you will know them) company…..they refused to twist the mod wires like I said etc….so their efforts didnt work….so muggins here had to come in all weekend, undo what they had done and redo it….for the Monday visit.But that’s when you’ve got to answer questions, because the gaffer dictates….on a forum I understand the grief, but at least you can just “click away”…but no, I totally know where you are coming from.Funny thing was, the more effort i put into explaining stuff to these guys..the more they stopped thinking and depended on me.

author: tggzzz
author_rank: Super Contributor
timestamp: November 10, 2023, 09:23:00 am
content: Quote from: Faringdon on November 10, 2023, 07:24:29 amWhatareyou on about?You complain about a situation in which other people "strip all the knowledge out of my brain and put it into theirs". That's fair enough, even though it could be considered par for the course.But then you do exactly that with contributors to this forum. Do you agree there's no way in which that isn't hypocritical?You ask questions and sucker contributors into spending time replyingwithout giving all the informationavailableand required. Do you agree that is grossly inconsiderate of other people's time, to the point of being rude?How many companies have employed you? I've seen claims of 42, but havenoidea whether that is remotely correct, and I would be grateful if you could set the record straight.

author: temperance
author_rank: Super Contributor
timestamp: November 10, 2023, 11:12:31 am
content: Inspecting the measurement conditions- something every engineer will do when something seems odd - under which Vce sat is being measured will quickly reveal why Vce sat for the PNP transistor is higher.The reason why is found in any descent textbook like Sedra smith microelectronic circuits chapter two or three I think which talks about electrons and holes. Do you agree that your question is of the novice kind and not something you expect from an engineer involved developing switching power supplies?There are probably more concerning matters to think about when driving a transistor into saturation.

author: Terry Bites
author_rank: Super Contributor
timestamp: November 10, 2023, 11:13:02 am
content: Why is pnp vs npn Vcesat an issue?

author: tggzzz
author_rank: Super Contributor
timestamp: November 10, 2023, 11:20:52 am
content: Quote from: temperance on November 10, 2023, 11:12:31 amI do agreeI expect many others do.Quote from: Terry Bites on November 10, 2023, 11:13:02 amBecause of the context he has - so far - withheld from us. Expect more details to dribble out.

author: Zero999
author_rank: Super Contributor
timestamp: November 10, 2023, 11:24:53 am
content: Quote from: Faringdon on November 10, 2023, 06:46:38 amNo. If anything, it means the opposite, but the question is pretty meaningless if one is comparing one part, with a completely different one.PNP transistors do have slightly poorer on characteristics, than NPN but the difference isn't as stark, as P vs N-channel MOSFETs.

author: Faringdon
author_rank: Super Contributor
timestamp: November 11, 2023, 01:25:00 am
content: QuoteIndeed Sir, well, i wouldst be not soaked, but truthfully, drenched, (even saturated) , in shame, if i hadnt actually also contributed to answering other forum questioners querys on here.And indeed, as discussed, if you were to peruse my personal mails, you would see an Aussie guy that is being helped with his PFC project.....then time hit me, and i hope to get back to help with the LLC bit.QuoteWe have a BJT circuit thats jittering on and off.....wondering if just using PNP, or just NPN, would be better...we can choose either version

author: tggzzz
author_rank: Super Contributor
timestamp: November 11, 2023, 10:04:38 am
content: Quote from: Faringdon on November 11, 2023, 01:25:00 amBeing polite and helpful in some circumstancesdoesn'texcuse repeatedly being rude and unhelpful in others.Invisible statements cannot be a mitigation. Make them visible to us and we will take them into account. If you don't understand that, peruse my PMs to see which member I gave £10000 to (or not).

author: temperance
author_rank: Super Contributor
timestamp: November 11, 2023, 01:34:14 pm
content: QuoteJittering on and off. What is that supposed to mean?As usual you hide circuit specifics and ask people for help. For an engineer deep into switching power supplies I would think you really know very well how to drive a BJT in class C, it's limitations and how to work around those.Can you explain all of us the problem you are facing? Or are you going to abandon your own topic and start a new one today?

author: tggzzz
author_rank: Super Contributor
timestamp: November 11, 2023, 02:10:11 pm
content: Quote from: temperance on November 11, 2023, 01:34:14 pmIt is rude and inconsiderate, isn't it.He won't explain the context, with the "justification" (and I use that word loosely) he stated here:Quote from: Faringdon on November 10, 2023, 07:24:29 amBut then I'm sure if we read thepersonal messageshe sent to another unnamed individual, we would change our opinion of him....Quote from: Faringdon on November 11, 2023, 01:25:00 amDraw your own conclusions.

author: temperance
author_rank: Super Contributor
timestamp: November 11, 2023, 02:35:20 pm
content: He is indeed very rude and using people on various boards to solve his problems.For example F is asking people on various boards to look up creepage and clearances so he doesn't have to. That's rude by all means. (the best of all is that he probably got wrong answers because the context to provide a meaningful answer is not given.) I would understand questions about standards if those would be about how they must be applied or interpreted. That happens to anyone involved in those matters and can lead to interesting conversations where some might have learned something.As counterweight he mentioned solving someones problem. The balance however is leaning very much towards one side.I wonder why F is still allowed to post here and other message boards.

author: tggzzz
author_rank: Super Contributor
timestamp: November 11, 2023, 03:09:17 pm
content: Quote from: temperance on November 11, 2023, 02:35:20 pmAfter Eternal September (a.k.a. the year September never ended) a new diversion arose on usenet. Whenever somebody asked a question that was obviously a homework or exam question, the tradition was to provide answers that were superficially correct - but anybody knowledgeable could recognise what was happening. Brownie points could be gained for amusing styleNow LLMs such as ChatGPT can - and will - fulfil the same functionEarlier in usenet history, too many people were using questions that they really ought to be looking up. That was brought into sharp focus by someone posting a simple question "What is the time?". Yes, the internet wasveryyoung back thenCouldn't succeed like that nowQuoteI don't know why treez was allowed to reincarnate himself as faringdon.Other boards might have a financial incentive: when the board is sold to another company, more hits -> increased valualuation. I see no evidence that is a consideration on this board.

author: nali
author_rank: Frequent Contributor
timestamp: November 11, 2023, 04:03:28 pm
content: Quote from: Faringdon on November 11, 2023, 01:25:00 amI can't be the only one here wondering, why doesn't your Aussie "friend" just join the forum and directly ask questions him/herself?(and why did you feel the need to delete that part from your earlier post?)

author: Zero999
author_rank: Super Contributor
timestamp: November 11, 2023, 04:12:32 pm
content: He doesn't bother me. There are far more annoying users. If he frustrates you so much, then don't bother replying. I don't understand why so many people reply, only to complain. It won't solve anything. Press the report button and move on.As far as the original topic is concerned: it's generally better to use NPN transistors, whenever possible. There's a much greater range to choose from and there appears to be more of a difference between PNP and NPN at higher voltages. A transformer can be used to drive a transistor, which can be useful on the high side and also means the voltage can be stepped down, which reduces the power dissipation in the base resistor.

author: magic
author_rank: Super Contributor
timestamp: November 11, 2023, 04:23:32 pm
content: Some people are addicted to drama.... and that's the secret reason why Dave keeps that guy here

author: tggzzz
author_rank: Super Contributor
timestamp: November 11, 2023, 05:23:51 pm
content: Quote from: nali on November 11, 2023, 04:03:28 pmAnticipating that possibility is why I include the relevant parts when I quote someone.Those that revise history usually have something to hide. Exception: those that explicitly note they are revising history, usually by inserting an "EDIT:..." and often usingstrikethroughto indicate what they are retracting.The latter are to be applauded for honesty and for considering other readers.

author: tggzzz
author_rank: Super Contributor
timestamp: November 11, 2023, 05:32:09 pm
content: Quote from: Zero999 on November 11, 2023, 04:12:32 pmThat's a fair point and question."Reporting" someone causes work for the moderators. They have enough to do as it is, so I avoid that except in clearcut spam/religion/etc posts.I don't like ignoring people, since I can often learn from those that have differing facts and opinions.If I could automatically ignore faringdon's posts and responses, I would. Ditto a couple of other infrequent posters. I could ignore them on usenet, but this isn't usenet.It is getting to the point where I will increase the load on the servers slightly, by manually ignoring his threads.Overall I like to think annoying people are doing it through ignorance or accident. Faringdon has now stated that isn't the case and that it is his deliberate style. Shame.