Claude,
I like discussing problems like this with you. Your points are cogent and pertinent to the discussion. And you are explanatory instead of denigrating. If you don't bother to answer this, it has been a pleasure to communicate with you. I hope to do so in the future.
With respect,
Ratch
Well, a FET is considered a VC device, whether current is involved or not. But suitability is not the question. We both agree on what is suitable. The question is internal control.In a FET, ther current in the gate is not leakage. A FET operates by injecting charge into the channel & inverting the region from p to n type or vice-versa. In a FET, the current is as important as the voltage. So is a FET VC or CC?
The answer lies in which type of power source should we employ at the gate to source. A dc constant current source, will indeed charge up the g-s capacitance & provide a voltage. But that voltage will ramp up indefinitely until the gate is punched through. A CCS is not a good way to drive a FET. But a CVS will charge up the gate to a particular voltage, prescribed to be less than the max g-s rating of the device. A good low internal impedance constant voltage source will provide enough current to charge up the gate in a short enough time to meet speed requirements.
Again, with a FET, or a bjt, current & voltage are BOTH indispensible. Neither device can operate w/ just 1 & not the other. I & V cannot exist apart. But some devices are more suited for "voltage drive". i.e. FET. But a bjt is much better suiired for current drive". It's that basic.
Yes, I understand what you are saying. There is an external stimulus that provides energy to generate Vbe. No doubt about that. What I am saying is that Vbe is at the location in the internal transistor where is controls the Ic or Ie if you will. I think this is a philosophical argument about what defines the control mechanism. You say it is the external stimulus, and I say it is the voltage that the base-emitter junction sees.Regarding the engine "driving" the train, I've been saying that "Singing Sue" is the engine. Of course the boxcars do not drive the train. It happens that Ib, Vbe, & Ie are the boxcars. Sue is the engine. Ib/Vbe/Ie are the boxcars. Sue provides the energy just like the engine in the train. Neither Ib nor Vbe nor Ie are a "source" of energy. Sue is that source. She must replenish her energy supply by breathing, drinking, eating & sleeping, just as the train engine eventually needs more fuel.
Yes, I understand and agree perfectly what you are saying about needing energy to control a BJT. To use another analogy to illustrate our differences, You consider the driver as controlling the steering of a car, whereas I consider the rack and pinion mechanism near the wheels as the controlling mechanism. Who is right? Philosophical question. This seems to be a good place to end this discussion.I don't know how to explain it better. I've been quite explicit. You have not addressed my energy conservation point. How can Vbe be the engine that provides the energy w/o Ib. The E field requires energy per time, or power. Power is the product of I & V. Sue's acoustic energy is transduced by the mic into electrical energy in the form of I & V. The energy viewpoint is unassailable. You cannot address it.
I like discussing problems like this with you. Your points are cogent and pertinent to the discussion. And you are explanatory instead of denigrating. If you don't bother to answer this, it has been a pleasure to communicate with you. I hope to do so in the future.
With respect,
Ratch