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  1. LvW

    Can someone explain me how a BJT works?

    I`ve got the impression that you are trying to use several different knowledge sources to reveal the "secrets" of the transistors (BJT and FET). In general, this is a good idea. However, I like to remind you that you have to be very careful because not everything which is printed or published in...
  2. LvW

    Can someone explain me how a BJT works?

    The working principle of the BJT was extensively discussed in this forum, see here: https://www.electronicspoint.com/posts/1690795/
  3. LvW

    Common collector configuraton

    Yes - agreed when operated in the saturation region.
  4. LvW

    Common collector configuraton

    Perhaps I couldn`t express myself clear enough - I didn`t speak about any "model". I was referring to the actual behaviour of the transistor when it is biased - as it is common practice in most amplifier applications - with a constant voltage at the base (voltage divider). In this case, we are...
  5. LvW

    Common collector configuraton

    May I point to the fact, that Vbe does not "drift" with rising temperatures? Instead, it is the collector current Ic that increases with the temperature - and we have to reduce Vbe externally by app. 2mV/K to bring Ic back to its former value. So - where is the advantage to view the transistor...
  6. LvW

    Op-amp task

    Before solving it one must know the task. So - what is the question?
  7. LvW

    Creating a variable wien bridge oscillator

    Yes - I believe you, of course. It resembles the classical oscillator principle. No problems with the slew rate for the LF351 at 150kHz? To the questioner: I am pretty sure that the circuit will also work if you replace the light bulb by a fixed resistor. The amplitude stabilization can be done...
  8. LvW

    Creating a variable wien bridge oscillator

    Don`t forget the slew rate limitations for higher frequencies. What is the slew rate for your amplifier?
  9. LvW

    Creating a variable wien bridge oscillator

    Of course, it is. Any oscillator circuit using the WIEN network (as invented by M. Wien) is a so-called "Wien oscillator". It is another question if and how you stabilize the amplitude (Diodes, FET, light bulb, OTA, thermistor,...).
  10. LvW

    Colpitts generator Pspice

    The used FET needs a negative bias voltage VGS - hence, a small source resistor would help. Mote than that - the crystal must be replaced by an inductance only.
  11. LvW

    Differential Amplifier - Differential Mode

    EEM - why do you start with part b) of the task? Does this mean that part a) is solved already? If not - start with a) because this opens the way to part b). By the way: Your result in post#5 is not OK (the right side of R3 is not grounded!)..
  12. LvW

    Unknown voltage of a Op amp

    And what about the polarity? +100mV or -100mV ?
  13. LvW

    Unknown voltage of a Op amp

    I think, you have found the above explanation somewhere. OK - that`s "legal", no problem. However, do you really understand the task of this resistor? For example, what could happen if R1=0 ? Would the opamp still work?
  14. LvW

    Unknown voltage of a Op amp

    May I ask you: What is your level of education? Are you a student or an interested amateur or...?
  15. LvW

    Unknown voltage of a Op amp

    Yes.
  16. LvW

    Unknown voltage of a Op amp

    So you can find the answer to your questions (post#6 and 8) by yourself?
  17. LvW

    Unknown voltage of a Op amp

    Yes - of course. Ohms law must be applied. However - what about the current ?
  18. LvW

    Unknown voltage of a Op amp

    In your circuit, R1 is an external ohmic resistor of - perhaps - som kOhms.
  19. LvW

    Unknown voltage of a Op amp

    The principle behind this simple answer is as follows: As long as the opamp is operated in its linear region (and negative feedback, as in your circuit, enlarges this region considerably) the input differential voltage of a real opamp is in the µV range (because of the very large open-loop gain...
  20. LvW

    Bode plot of RC circuit

    Are you able to ask a specific question? What is "it"? What is it you don`t understand?
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