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Article #15456Re: Query - How valves and transistors work
From: John Woodgate
Date: Sat, 02 Jan 1999 00:00
Date: Sat, 02 Jan 1999 00:00
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<76jqau$ltt$1@computer.my.domain>, Duncan Barclay <dmlb@ragnet.demon.co.uk> wrote: >This is NOT correct. For certain far-out values of 'correct'. > >How does this explain the way a long-tailed pair works? You took me to task for confusing device physics with circuit configuration. So you can't fairly use that argument now. You had some sort of a case if you confined the matter to device physics, but that was not appropriate at the level of the enquirer. It was a Musoft answer - correct but utterly unhelpful. > >A BJT allows you to control a current by varying the base emitter >voltage. > In an extremely non-linear manner. If one adopts this concept exclusively, it appears that it is not possible to make a linear (non- grossly distorting) amplifier. >Certain circuit configurations make it appear that you can control the >collector current by changing the base current. It doesn't just 'appear' - you can and do. > But as this ratio >varies with temperature, device, process, batch, which direction the >circuit board is facing, it's not very useful. So why is it quoted in (almost?) every BJT data sheet? It's one thing to be formally and academically correct. It is quite another to insist that no other approach has any value at all. -- Regards, John Woodgate, Phone +44 (0)1268 747839 Fax +44 (0)1268 777124. OOO - Own Opinions Only. You can fool all of the people some of the time, but you can't please some of the people any of the time.
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: fcc1a,6f59d673fceaf3aa X-Google-Attributes: gidfcc1a,public X-Google-Thread: 111d0a,6f59d673fceaf3aa X-Google-Attributes: gid111d0a,public X-Google-Thread: 114713,6f59d673fceaf3aa X-Google-Attributes: gid114713,public X-Google-Thread: 107d45,6f59d673fceaf3aa X-Google-Attributes: gid107d45,public X-Google-Thread: 1110fe,6f59d673fceaf3aa X-Google-Attributes: gid1110fe,public X-Google-Thread: 10b271,6f59d673fceaf3aa X-Google-Attributes: gid10b271,public X-Google-Thread: 1118be,6f59d673fceaf3aa X-Google-Attributes: gid1118be,public X-Google-Thread: 112d1e,6f59d673fceaf3aa X-Google-Attributes: gid112d1e,public From: John Woodgate <jmw@jmwa.demon.co.uk> Subject: Re: Query - How valves and transistors work Date: 1999/01/02 Message-ID: <59q9yQA3Bdj2EwN3@jmwa.demon.co.uk> X-Deja-AN: 428040168 Distribution: world X-NNTP-Posting-Host: jmwa.demon.co.uk:158.152.135.100 References: <368691bc.0@stargazer.actinet.net> <76b08g$jo4$1@news-1.news.gte.net> <76b8i0$rqm$1@computer.my.domain> <fuNEGVAumei2EwR5@jmwa.demon.co.uk> <76dss3$fhq$1@computer.my.domain> <d1dLzCAjKri2EwAr@jmwa.demon.co.uk> <76ibj9$rhc$1@computer.my.domain> <76ja03$gud$1@news-2.news.gte.net> <76jqau$ltt$1@computer.my.domain> X-Complaints-To: abuse@demon.net X-Trace: news.demon.co.uk 915297746 nnrp-11:18064 NO-IDENT jmwa.demon.co.uk:158.152.135.100 Organization: JMWA Electronics Consultancy MIME-Version: 1.0 Newsgroups: sci.physics,fj.sci.physics,sci.physics.electromag,tnn.physics,news.electronics.basics,sci.electronics.basics,sci.electronics.components,sci.electronics.design,sci.electronics.misc