Claude Abraham
Member
Oblivion,
Well then, don't keep it a secret. Bring it on.
Which nonsense is that? We talked about several subjects.
Oh, you mean about what defines Ohm's law. I never said that Ohm's law was not Ohm's law. I said that Ohm's law was not the triad of V=I*R, etc. It was instead the linearity of resistance of a material. The policy of not pointing out a truth because some people might not believe it or would argue about it is silly. It is only "trolling" if you cannot back it up with facts. Your statement of not believing what I said denigrates two good physics books and the professors that wrote them. You should objectively peruse this link. https://www.electro-tech-online.com/threads/buy-dso-oscilloscope.222/
Just because voltage and current have a relationship to each does not mean either one controls a device. In a BJT, it is the base-emitter voltage that controls the emitter/collector current while in the active region. That is determined by the physics of the BJT. You can derive models that show either current or voltage dependency, but that does not reveal the physics of the device.
Ratch
Eli the ice man demolished that theory. You can't refute Eli. Time is not negotiable. Ie/Ib change w/o Vbe, then Vbe catches up. End of debate. Vbe is a loss incurred crossing the junction. Vbe is not an active power source, like a generator or battery. It is literally the energy per unit charge LOST crossing the juction.
When a source, such as a mic, outputs a signal I./V, via a mic cable, the signal, both I & V transit through the cable and reach the b-e junction. The V & I are already present, the cable impedance Z0 = V/I. If the terminating load resistance is different from Z0, a reflection occurs, I/V return to the source where another reflection occurs, eventually settling.
Transmission line theory is generally not used for wavelengths longer than 20 times the distance spanned. But it must be acknowledged if we wish to discuss which is in control. Timing is all important. The mic outputs a signal and is totally oblivious to Ie/Vbe?Ib that lies ahead. Mic only sees Z0 the cable impedance. Ie is not a by product of Vbe, it is created when singer's acoustic energy is transferred to mic element. I & V both co-exist at that point and eventually reach base of input amp stage. If stage has large ac degeneration, the impedance of the stage input along with cable Z0 determines reflection coefficient. Eventually when settling takes place Ie still leads Vbe chronologically.
The notion that Vbe controls Ie is nothing more than an assumption which as of yet has been unable to withstand scrutiny. In addition, do you know the difference between **voltage drop* and *emf*? An emf is a ratio of energy GAINED per unit charge, vs. a drop which is energy LOST per unit charge. The potential barrier at the b-e junction, according to you, must be lowered in order for Ie/Ib to increase. Yet Shockley states that increased Ie/Ib is linked to increased Vbe.
Even before Vbe changes, I & V from the mic are established. If the I value is an increase over a moment ago, Vbe has not changed yet. I enters b-e junction and the increased carrier density eventually forces an increase in barrier potential. Clearly the mic/singer is in control of everything. The singer increases acoustic energy, increasing mic element I/V, increasing Ie/Ib, then Ic increases due to larger Ie. Vbe eventually catches up to the new increased value, but Ic increased due to increase in Ie.
Physics of bjt is quite clear. I re-iterate, Shockley states the relation between I & V, for an LED, diode, bjt, SCR, etc. V does not control I, not in the forward direction at all. My switch mode power supply illustration addresses that point. Please review.