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  1. R

    Transistor bias configuration

    Yes, one can set the base current by making Vbe comply with the desired value. As long as it is realized that the Vbe is controlling the base and collector current even if the value of Vbe is unknown at the base current value. It is ambiguous to say that the voltage or current is being biased...
  2. R

    Transistor bias configuration

    If the OP asks an involved and open question, he/she has to be prepared for a indefinite answer and a possible involved discussion afterwards.. Ratch
  3. R

    Transistor bias configuration

    No, you are wrong about that. And so is "Talking Electronics" if they aver that. Here is the reason why. Once a transistor is fabricated, nothing anyone can do externally will change its internal operation. It will operate the same way no matter what circuitry or voltages are attached to it...
  4. R

    Transistor bias configuration

    Your link points to a somewhat long thread. With which posts in that thread do you agree? Not every post in that thread contains correct information. Ratch
  5. R

    Transistor bias configuration

    The way a transistor works is not affected by the way it is biased. A transistor responds to voltage on its input and output, and does not care how that voltage is developed. The applications are countless and limited only by the imagination. Ratch
  6. R

    large power amplifier

    OK, 33000uf *4 caps * 2000 ohms/4 = 66 sec, or a time constant of about 1 minute. So in 1 minute the voltage will drop to e^-1 or 37% of its max value and in 2 minutes it will drop to e^-2 or 13.5% of its max value. Ratch
  7. R

    large power amplifier

    Yes, those are called "bleeder resistors". If I knew the capacitance value of each of those caps, I could calculate the RC time constant of that circuit. Ratch
  8. R

    More length in wire

    You should be more specific. For instance, if I apply 12 volts across 1200 feet of wire, then there will be a 12 volt drop across the total 1200 feet of wire. Now, if I increase the length of wire to 2400 feet, then there still will be a 12 volt drop across the total wire. Is that what you...
  9. R

    Why does the current always remain the same in a series circuit?

    Current is the rate of charge movement. Once the charge moves is in a single conductive path like a series circuit, there is no way that additional charge can be added or taken away. Therefore, all the charge is constrained to move at the same rate, and the current will be the same throughout...
  10. R

    Relationship of frequency and capacitance.

    Do hydraulics folks use electrical analogs to study their craft. No? Then why should folks studying electronics use hydraulic analogies for their studies? Why not accept that a capacitor is charged with energy or energized, and study capacitors using energy as a quantity? The bucket brigade...
  11. R

    Transistors / hfe / Active region conflicts

    Because internal device physics correctly describes how a device really works. The terminal characteristics are determined by the internal device physics and the external components. Internal device physics are relevant here, too. Perhaps. Ratch
  12. R

    Transistors / hfe / Active region conflicts

    Still no physics explanation from you on how a current can influence the depletion region and thereby the charge flow across the PN junction. Isolation of the BJT input is not a factor. You are still hung up on design techniques and empirical reasoning to explain how a transistor works. In...
  13. R

    emission current and electron energy

    That would appear to be the case. Don't forget that if the anode is close enough to the filament, it might reduce the effect of the space charge around the filament, and contribute to increased emission current. I am only listing factors that might affect filament current. I don't have the...
  14. R

    emission current and electron energy

    I would think that the emission current is dependent on the ability of the filament to supply electrons, and that in turn is dependent on the temperature of the filament and the space charge around it. If you crank up the anode voltage, each electron will reach the anode faster, but without...
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    Transistors / hfe / Active region conflicts

    A current source is not part of the device. It is a external to the device, and its addition makes a current amplifying circuit. This was pointed out to you earlier. You cannot put a device into a circuit and say the device has the same characteristics as the circuit to which it is embedded...
  16. R

    P-Type semiconductor. Which band does ''hole'' current occur in?

    Hole current occurs in the valance band. Hole current in the valance band will not occur until the electrons in the valance band jump to fill the holes just above the valance band. Otherwise there will be no holes in the valance band to conduct current. The conduction band conducts...
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    Transistors / hfe / Active region conflicts

    Empirical methods are great for determining what a device does or using a device. But, it does not disclose how a device works. You need to understand the underlying physics to do that. That is why just looking at a Ib vs Ic graph does not tell you what is in control (neither is controlling...
  18. R

    Transistors / hfe / Active region conflicts

    Those curves were made by empirical methods. Therefore, they do not show cause and effect. Any attempt to use those curves to show the physical relationship of current and voltage is bogus. Only a physics explanation can determine cause and effect. Ratch
  19. R

    Transistors / hfe / Active region conflicts

    Before you can make that claim, you have to explain how a current can influence the depletion region of the diode junction. The depletion region current is influenced primarily by the diffusion process and the voltage applied across it. You can calculate what the voltage would be if such and...
  20. R

    Transistors / hfe / Active region conflicts

    I anticipated you would present an argument like that. The answer is that the current source is supplying the voltage which lowers the back-voltage of the depletion region and controls the current that is caused by the diffusion process. Therefore, it is a voltage that controls the current no...
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