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  1. LvW

    Impressions from Bolivia

    Welcome home LvW if you would like to, please post a few choice photos of your trip in the off-topic members lounge section of the forum .... would be cool to see them :) Dave Well - I shall follow Dave´s recommendation. We (me and my wife) were in Bolivia from mid of March until beginning of...
  2. LvW

    How a BJT Transistor works (base current version)

    This answer would be helpful (without the rest) if you would be a little more precise: What means "signal"? Voltage or current? In any case, from this I derive that now you agree that the emitter current is varied (controlled) either by a voltage signal (VBE) or by a current signal (IB). Is...
  3. LvW

    How a BJT Transistor works (base current version)

    Only some short remarks from my side: * Claude - I am really disappointed and surprised about the way you try to "discuss". Do you really think it is necessary to teach me that "emitter current and base current are NOT the same thing"? Where did I mention such silly stuff? Please, try to be...
  4. LvW

    filter design

    What does this mean: "But it`s affecting"? According to your measurements, simulations or theoretical analyses? What are you speaking of - active or passive filters? In general, the signal level plays a role in non-linear circuits only. Is there any non-linearity(overdrive)?
  5. LvW

    Small signal amplifier problem?

    Mymla - the shown circuit is one of the classical amplifier circuits to be found in nearly each text book. Answering the listed questions requires some basic knowledge of transistor fundamentals as for example. What did you learn about transistors and their properties? Are you familar with the...
  6. LvW

    How a BJT Transistor works (base current version)

    Adam - thank you. Yes, the trip (through Bolivia and Chile) was - of course - interesting (and, sometimes, exhausting because of a very high trafiic noise level). My son lives in Bolivia since 3 years (Cochabamba) and he was celebrating his 30th birthday.
  7. LvW

    Finding cutoff frequency with Short/Open Circuit Time Constant

    Can you tell us upon which rule your method (open circuit/short circuit) is based on?
  8. LvW

    How a BJT Transistor works (base current version)

    Gentlemen - I was absent for 6 weeks (travelling through Bolivia/Chile) and I am a bit surprised that this funny discussion does not yet came to an end. I am sure, we cannot convince Claude - but that´s not OUR problem. I think, one of his fundamental misunderstandings is summarized in his...
  9. LvW

    problems encountered when building an analog computer for simulating 2nd order diff eq

    Three comments from my side: 1.) I think, you must not care about offset voltages/currents because this is a problem for "self-standing" integrators only. However, in your case, both integrating blocks have an overall dc feedback (acting like ohmic resistors parallel to the integrating...
  10. LvW

    impedance of amplifier

    Well - a common collector stage can placed BETWEEN a signal source having a high source impedance and another stage having rather small input impedance. Thus, the common-collector stage acts like a "matching network" between source and load. Without this stage (large input resistance, small...
  11. LvW

    BJT Transistors

    ...and Vbe vs. Ic characteristic. However, to be exact we should also mention that BOTH base currents are to be provided by the left part of the circuit. This causes a kind of unsymmetry within the current mirror. More than that, the voltages Vce differs considerably - thus causing another...
  12. LvW

    BJT Transistors

    Just to avoid misunderstandings: When writing "gain" - do you mean "current gain" (beta)? In this case, you are in error. The value of Ic depends on Vbe only. It is only the base current that differs in case of different beta values.
  13. LvW

    How a BJT Transistor works (base current version)

    Hi Ratch - I was prepared to answer Claude, however I can spend my time for some more important actions. The reason is because you already have done the job. It is really surprising (funny?) that somebody with his background ("near completion of Ph.D.") constantly is repeating the story about...
  14. LvW

    Simple passive low pass filter

    "...to block any frequencies above about 300 cps." I suppose you know that it is not possible "to block" frequencies above the so-called "cut-off" frequency. A first order RC lowpass - as envisaged by you - attenuates unwanted frequencies only with an attenuation rate of 20dB/decade. For better...
  15. LvW

    problem with the integration of DC analysis

    The main problem in this circuit is that the switching action of the JFET works fine in AC analysis, but not in the DC analysis. Yes - a circuit diagram would be very helpful. However, one question: Do you expect to see any "switching action" in a DC analysis?
  16. LvW

    How a BJT Transistor works (base current version)

    Claude - in all technical discussions, I try to be as objective as possible without any personal remarks - however, I cannot resist to ask you: Are you an engineer or a physician or a philosopher or something else? To me, it is really surprising to see how somebody is trying to complicate...
  17. LvW

    How a BJT Transistor works (base current version)

    Hi Steve, your answer reminds me again on one of your posts (post#16) which was a reply to my assertion that - for my opinion - a beginner needs the voltage-control approach in order to understand RE feedback. The contents of your reply was a short comment („That's absolute rubbish“) and a...
  18. LvW

    How a BJT Transistor works (base current version)

    "I've responded plenty. You ask for proof, I give it, ask for examples, I give them." I cannot find in all your post´s any example or observation which can be explained with current control only - or which cannot be explained with Vbe-control. Please, help me to find it. Claude, continuously...
  19. LvW

    How a BJT Transistor works (base current version)

    Ratch - fully agreed. And I am happy that there are some guys who are able to explain things on charged carrier level. But - in addition - I have collected some test, measurements, observations which can support your findings. That`s because i think (feel) that that it must be possible to find...
  20. LvW

    How a BJT Transistor works (base current version)

    Adam - did the transistor survive? (I suppose you know what I am referring to?).
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