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Article #15457Re: Query - How valves and transistors work
From: Duncan Barclay
Date: Sat, 02 Jan 1999 00:00
Date: Sat, 02 Jan 1999 00:00
42 lines
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3490 bytes
In article <76kgnq$lin$1@news-1.news.gte.net>, Doug <do@not.spam> writes: > Duncan Barclay wrote: >> A BJT allows you to control a current by varying the base emitter >> voltage. > > Your claim that the BJT is also a voltage controlled device > does work as a model. No one is denying that. But, the > effect of the voltage on the BJT is to allow current > injection to occur. Precisely, 1) VBE voltage controls current injection at BE juntion 2) current injection at the BE junction controls collector current Cause and effect.... > In other words, your voltage source must include current. Can't parse that, by definition a voltage source can supply an infinite ammount of current, but it does not include it. > Under the assumption that the BJT is ONLY a voltage device is to say > that under a perfect model of a BJT, no current injection is the > desired state. It is not. Last I saw, BOTH the EM and GP models > have current injection forms. Gee, I wonder why ... To get fundemental, all active devices are voltage controlled because nature does not provide a current source (no monopoles). BJTs, valves, FETs are all govered by electrostatic fields. Remember Schrodinger's Equation, or band bending or Laplace's Law or the Boltzmann Transport Equation? All the eqautions are of the form [charge_ammount, charge_momentum, charge position] = f(electric field) Duncan -- ________________________________________________________________________ Duncan Barclay | God smiles upon the little children, dmlb@ragnet.demon.co.uk | the alcoholics, and the permanently stoned. ________________________________________________________________________
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 10b271,6f59d673fceaf3aa X-Google-Attributes: gid10b271,public X-Google-Thread: fcc1a,6f59d673fceaf3aa X-Google-Attributes: gidfcc1a,public X-Google-Thread: 112d1e,6f59d673fceaf3aa X-Google-Attributes: gid112d1e,public X-Google-Thread: 107d45,6f59d673fceaf3aa X-Google-Attributes: gid107d45,public X-Google-Thread: 1118be,6f59d673fceaf3aa X-Google-Attributes: gid1118be,public X-Google-Thread: 111d0a,6f59d673fceaf3aa X-Google-Attributes: gid111d0a,public X-Google-Thread: 1110fe,6f59d673fceaf3aa X-Google-Attributes: gid1110fe,public X-Google-Thread: 114713,6f59d673fceaf3aa X-Google-Attributes: gid114713,public From: dmlb@ragnet.demon.co.uk (Duncan Barclay) Subject: Re: Query - How valves and transistors work Date: 1999/01/02 Message-ID: <76l9k3$iet$1@computer.my.domain> X-Deja-AN: 428057345 Distribution: world X-NNTP-Posting-Host: ragnet.demon.co.uk:158.152.46.40 References: <368691bc.0@stargazer.actinet.net> <76b08g$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$1@computer.my.domain> <76kgnq$lin$1@news-1.news.gte.net> Content-Type: text/plain; charset=us-ascii X-Complaints-To: abuse@demon.net X-Trace: news.demon.co.uk 915301893 nnrp-06:17199 NO-IDENT ragnet.demon.co.uk:158.152.46.40 Organization: Ragnet, a small network of machines at Raggy's home. 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