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From: John Larkin on 14 May 2010 13:10 On Fri, 14 May 2010 10:09:55 -0400, Spehro Pefhany <speffSNIP(a)interlogDOTyou.knowwhat> wrote: >On Fri, 14 May 2010 10:59:21 GMT, Jan Panteltje ><pNaonStpealmtje(a)yahoo.com> wrote: > >>On a sunny day (Thu, 13 May 2010 17:48:41 -0700) it happened John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in >><i37pu594178305v2a62vb99d263og1tfau(a)4ax.com>: >> >>>I like this as a test: >>> >>> >>> >>> +10V >>> | >>> | >>> | >>> | >>> c >>> +5V--------------b >>> e >>> | >>> | >>> 1K >>> | >>> | >>> | >>> | >>> gnd >>> >>> >>>What's the base voltage? >>> >>>What's the base current? >>> >>>What's the emitter voltage? >>> >>>What's the collector current? >>> >>>What's the collector voltage? >>> >>>Any other comments? >>> >>> >>>I'm not kidding. One "experienced ee" said that, since the transistor >>>is saturated, the collector voltage is zero. A tech applicant said >>>that the base voltage is 0.6. >>> >>>Some people got it right, but nobody has mentioned oscillation so far. >>> >>>John >> >>How many asked if it was germanium or Si? >>Would be my first question. > >Could be _both_, or perhaps neither- such as a III-V material (but I'm >not sure where to buy the latter in a discrete BJT). There are a few discrete HBTs for sale. Haven't tried them. John
From: Vladimir Vassilevsky on 14 May 2010 13:18 John Larkin wrote: > On Fri, 14 May 2010 10:59:21 GMT, Jan Panteltje > <pNaonStpealmtje(a)yahoo.com> wrote: > > >>On a sunny day (Thu, 13 May 2010 17:48:41 -0700) it happened John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in >><i37pu594178305v2a62vb99d263og1tfau(a)4ax.com>: >> >> >>>I like this as a test: >>> >>> >>> >>> +10V >>> | >>> | >>> | >>> | >>> c >>> +5V--------------b >>> e >>> | >>> | >>> 1K >>> | >>> | >>> | >>> | >>> gnd >>> >>> >>>What's the base voltage? >>> >>>What's the base current? >>> >>>What's the emitter voltage? >>> >>>What's the collector current? >>> >>>What's the collector voltage? >>> >>>Any other comments? >>> >>> >>>I'm not kidding. One "experienced ee" said that, since the transistor >>>is saturated, the collector voltage is zero. A tech applicant said >>>that the base voltage is 0.6. >>> >>>Some people got it right, but nobody has mentioned oscillation so far. >>> >>>John >> >>How many asked if it was germanium or Si? >>Would be my first question. > > > An interviewee could certainly ask questions, or mention assumptions. > > Can you still buy germanium transistors? Would that affect many of the > answers much? You can buy germanium transistors in China if you need them. It is kinda nostalgic to see old style metal cans. BTW, on the matter of Jan's questions: 90% of experienced EEs think that Vce is 0.6V for silicon BJT in saturation mode. This misconception is surprisingly common. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
From: John Larkin on 14 May 2010 14:28 On Fri, 14 May 2010 12:18:27 -0500, Vladimir Vassilevsky <nospam(a)nowhere.com> wrote: > > >John Larkin wrote: >> On Fri, 14 May 2010 10:59:21 GMT, Jan Panteltje >> <pNaonStpealmtje(a)yahoo.com> wrote: >> >> >>>On a sunny day (Thu, 13 May 2010 17:48:41 -0700) it happened John Larkin >>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in >>><i37pu594178305v2a62vb99d263og1tfau(a)4ax.com>: >>> >>> >>>>I like this as a test: >>>> >>>> >>>> >>>> +10V >>>> | >>>> | >>>> | >>>> | >>>> c >>>> +5V--------------b >>>> e >>>> | >>>> | >>>> 1K >>>> | >>>> | >>>> | >>>> | >>>> gnd >>>> >>>> >>>>What's the base voltage? >>>> >>>>What's the base current? >>>> >>>>What's the emitter voltage? >>>> >>>>What's the collector current? >>>> >>>>What's the collector voltage? >>>> >>>>Any other comments? >>>> >>>> >>>>I'm not kidding. One "experienced ee" said that, since the transistor >>>>is saturated, the collector voltage is zero. A tech applicant said >>>>that the base voltage is 0.6. >>>> >>>>Some people got it right, but nobody has mentioned oscillation so far. >>>> >>>>John >>> >>>How many asked if it was germanium or Si? >>>Would be my first question. >> >> >> An interviewee could certainly ask questions, or mention assumptions. >> >> Can you still buy germanium transistors? Would that affect many of the >> answers much? > >You can buy germanium transistors in China if you need them. It is kinda >nostalgic to see old style metal cans. > >BTW, on the matter of Jan's questions: 90% of experienced EEs think that >Vce is 0.6V for silicon BJT in saturation mode. This misconception is >surprisingly common. Really? I didn't know that 90% of EEs were that dumb. That's terrifying. I recently did some saturation measurements on a BCX70 and was surprised myself... but at least I didn't expect 0.6. ftp://jjlarkin.lmi.net/BCX70_curves.pdf I bet few EEs know how to make an NPN saturate to exactly 0 volts. John
From: Winston on 14 May 2010 14:34 On 5/13/2010 10:37 AM, Vladimir Vassilevsky wrote: The good interface is a big green square button with inscription: "I WANT EVERYTHING RIGHT NOW !" The best interface is a big green round button without any inscriptions. VLV (...) > Applied filter "Idiots" to message from Winston <Winston(a)bigbrother.net> > - OT: Working with Plastics (Prototype) at 2010-05-12 16:24:00 Action = > Delete "But don't ask me what I think of you, I might not give you the answer that you want me to." -- Peter Green --Winston
From: Jan Panteltje on 14 May 2010 14:52
On a sunny day (Fri, 14 May 2010 08:47:22 -0700) it happened John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in <01squ5ptt9hucaddla4ek5088r7s695p4s(a)4ax.com>: >On Fri, 14 May 2010 10:59:21 GMT, Jan Panteltje ><pNaonStpealmtje(a)yahoo.com> wrote: > >>On a sunny day (Thu, 13 May 2010 17:48:41 -0700) it happened John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in >><i37pu594178305v2a62vb99d263og1tfau(a)4ax.com>: >> >>>I like this as a test: >>> >>> >>> >>> +10V >>> | >>> | >>> | >>> | >>> c >>> +5V--------------b >>> e >>> | >>> | >>> 1K >>> | >>> | >>> | >>> | >>> gnd >>> >>> >>>What's the base voltage? >>> >>>What's the base current? >>> >>>What's the emitter voltage? >>> >>>What's the collector current? >>> >>>What's the collector voltage? >>> >>>Any other comments? >>> >>> >>>I'm not kidding. One "experienced ee" said that, since the transistor >>>is saturated, the collector voltage is zero. A tech applicant said >>>that the base voltage is 0.6. >>> >>>Some people got it right, but nobody has mentioned oscillation so far. >>> >>>John >> >>How many asked if it was germanium or Si? >>Would be my first question. > >An interviewee could certainly ask questions, or mention assumptions. > >Can you still buy germanium transistors? Yes. >Would that affect many of the >answers much? Yes >John Especialy for you who thinks in femtos. |