Re: Re: Functional vs. causal
EDIT: I wrote a long reply, then decided to scrap it. No need to fuel another religious war.
If you want/need to continue this debate, please start a new thread. I promise to contribute, if you hold the personal remarks. A friendly warning though: I may be your worst nightmare on such topics
EDIT: I wrote a long reply, then decided to scrap it. No need to fuel another religious war.
If you want/need to continue this debate, please start a new thread. I promise to contribute, if you hold the personal remarks. A friendly warning though: I may be your worst nightmare on such topics
Hi Claude,
---Of course we must forward bias the b-e junction as well. Only a superconductor can carry I w/o V.---
With not enough Vbe, no base current (except the leaking one).
Is that not preeminence on voltage over current regarding the command of bipolars ?
We had the same discussion on a french forum a few monthes ago, and a reference to superconductors also came in.
---Of course we must forward bias the b-e junction as well. Only a superconductor can carry I w/o V.---
With not enough Vbe, no base current (except the leaking one).
Is that not preeminence on voltage over current regarding the command of bipolars ?
We had the same discussion on a french forum a few monthes ago, and a reference to superconductors also came in.
Re: NFB clamp
Hi Glen,
I feel flattered that you've adopted my idea of the nfb clamp. However, you have only used the feedback part. So, I would have been even more flattered if you also had adopted the other part (which monitors Vce of the drivers), instead of adapted it. ....................
For further reading, please look here: http://www.diyaudio.com/forums/showthread.php?postid=1825871#post1825871
Cheers,
Edmond.
G.Kleinschmidt said:
Hi Glen,
I feel flattered that you've adopted my idea of the nfb clamp. However, you have only used the feedback part. So, I would have been even more flattered if you also had adopted the other part (which monitors Vce of the drivers), instead of adapted it.
....................For further reading, please look here: http://www.diyaudio.com/forums/showthread.php?postid=1825871#post1825871
Cheers,
Edmond.
Re: Re: minimum stage count
Hi Anatoliy,
Indeed, at first sight some resemblance. But it are the many details that matter (most of them not shown in my post). The improvement in performance of my 'snake' is huge compared with that TO-3 thingy.
Cheers,
Edmond.
Wavebourn said:Hmmm... Now it looks like a snake pretending to be a rope.
I've seen a very similar thingy in To-3, long time ago...
Edit: http://www.datasheetcatalog.org/datasheet/elantec/ELH0021K.pdf
Hi Anatoliy,
Indeed, at first sight some resemblance. But it are the many details that matter (most of them not shown in my post). The improvement in performance of my 'snake' is huge compared with that TO-3 thingy.
Cheers,
Edmond.
syn08 said:
I got an even better argument:
J=sigma*E
E=-grad V
Once again, circular arguments. These are 2 functional relations. Just as J = sigma*E, it is equally true that E = rho*J. E & J are inclusive. Neither comes first. This is an identity. But this Ohm's law relation only covers *conduction* current. The ib I referred to as needed to change the E field value is *displacement* current. The circuit equivalent of J = sigma*E is V = I*R. Agan this is only for conduction current. In the circuit domain, i = C*dv/dt. The b-e junction capacitance is non-linear so an extra term is needed i = C*dv/dt + v*dC/dt. So Ohm's law J = sigma*E does not cover this current. With the displacement component of Ic, I used the notation "Icdisp". To change the E field in the base-emitter junction, I used "ib", but I should have used "ibdisp" to be more clear. Also, the "ibdisp" component of current chronologically precedes the vbe, so that it cannot be an effect of vbe.
E = -grad V is also an identity, It is a functional relation. I don't normally assume what a person is trying to state, but I have a gut feeling that you think that V is the cause of E. It is not. E is not caused by V. V is defined as the integral of E.dl. First we start with Coulomb's law, then we establish the field relation F = q*E. V is then defined from E. The gradient is a functional relation, not causal. Also the gradient relation is valid only for fields due to charges. The complete expression is:
E = -grad V - dA/dt + (u X B).
Once again, I & V mutually coexist. Neither is the cause of the other. Attempting to establish either ib, vbe, or ie as "causal" is a chicken and egg vicious circle.
When we externally drive a bjt, we control Ie to establish Ic, hence we say a bjt is current controlled.
But internally is it ib, vbe, or ie, that "causes" a change in the E field? The answer is all 3 are equally responsible. The change in collector current, ic, is "caused" by a simulataneous change in ib-vbe-ie all in unison with no pecking order.
Field theory & semiconductor physics clearly describe the ib-vbe-ie relation as mutual. Best regards.
Claude
Claude Abraham said:
Don't really understand why you think yours is bigger, but if you want to redefine and rewrite the solid state physics as we know it, go ahead, nobody's going to stop you. I recall some mathematicians trying to re-write the math without the Zermelo's axiom. Almost 100 years later, before they gave up, they made it to the two integers addition theorem.
Best regards and good luck.
Wavebourn said:Gentlemen;
Can you please stop fighting for a while?
Thank you.
Suppose, we have a NPN transistor.
We grounded a base and supplied it's emitter by current from + rail that has enough voltage for E-B junction to breakdown.
Now, what shall we measure on collector in respect to base?
Why?
So, did anybody measure?
SPICE won't help.
It's appear to be a current controlled voltage source. Since an output voltage is negative, where it comes from, if no negative supply is connected to the device?
syn08 said:
Who's trying to "rewrite" physics? Fairchild, TI, & On Semi describe the bjt as current controlled, and you're saying that I am the one rewriting physics. How do you get around conservation of energy. How do you vary the E field value by only varying vbe? How can E change unless ib & vbe are BOTH varied. Conservation of energy is immutable. My position considers all the physics laws, not just hand selected partial relations.
As far as "mine is bigger", I don't think so. I'm not out to "win". If this is a duel to determine who "wins", then count me out. I don't believe in that. I'll discuss this with anybody on polite terms. I'm not out to prove superiority. But when a contrarian insists that the semi makers are all wrong, and that they have the truth, I have to address them.
I'm not out to win, and I claim no superiority to anyone. I learned this stuff one day at a time. I wasn't born knowing it. I've had 5 courses on semiconductor physics. One as an undergrad from the physics dept. One as an MS grad from the EE dept. Three from the PhD program I'm currently in. At the atomic level, bith the bjt and FET are *charge controlled*. This is getting too long.
To John Curl. Chickens and eggs is my position as well. My posting history confirms this. Is transistor action due to ib or vbe or ie? My position has always been ALL 3. There is no causality. They coexist. If that is your position as well, then we agree. BR.
Claude Abraham said:
Doing so, they call MOSFETS voltage-controlled devices, that are "easy to drive".
I have to disagree: they are charge controlled devices, and it takes an enormous power dissipated to charge/discharge them in order to drive on reasonable frequencies.
It was me who is guilty. Debates started after I called BJT a current controlled device.
Sorry for non-intentional provocation of a religious war between scientists who worked during a cold war on opposite sides of the fence.
Wavebourn said:
Doing so, they call MOSFETS voltage-controlled devices, that are "easy to drive".
I have to disagree: they are charge controlled devices, and it takes an enormous power dissipated to charge/discharge them in order to drive on reasonable frequencies.
It was me who is guilty. Debates started after I called BJT a current controlled device.
Sorry for non-intentional provocation of a religious war between scientists who worked during a cold war on opposite sides of the fence.
But I've always insisted that the bjt is charge-controlled, down at the mIcro level. The current controlled view is a mAcro level view. You're not guilty of anything by calling a bjt a CCCS. You are in agreement with semiconductor OEMs, as far as the mAcro view goes. At the mIcro level, we agree that FETs and bjts are charge controlled.
We agree, hence no need for you and I to argue. Best regards.
Claude Abraham said:
You too!
Now, since we are agree, how would you explain this phenomenon? http://www.diyaudio.com/forums/showthread.php?postid=1826093#post1826093
Edmond Stuart said:hint: LED
Old news. This riddle was published in EDN back in the 80's by Jim Williams. The collector was stated to go negative slightly with photon emission taking place.
Still, it's a nice thought problem. I happen to enjoy these. If you have more, please share. Thanks in advance.
Claude, thanks for your input.
This is one of the areas that separates engineering from popular electronics. Sometimes it is useful, mostly it is not.
As I said before, in the early days, and even today, sometimes, such as making power amp output stages, you have to realize that BETA is neither infinite or super linear. You also have to look at the graphs showing BETA vs IC and NOTE THE SCALING! Is it semi-log, is it log-log?
Just for fun, convert your favorite output transistor to linear, linear, and see what you get!
This is a real 'eye opener'.
Other times, the BETA is so high and the circuits are so redundant, because it is easy and cheap these days to just add an extra active device or two (or 20) that the effect of BETA is reduced to secondary performance, and Gm becomes useful and necessary to keep an eye on.
There has been a 'revolution' in circuit design since the 1960's primarily due to IC development that uses both differential and current mirror circuitry almost exclusively and virtually a 'cult' seems to be built around this design technique. It IS useful for IC's, but it is difficult and expensive to do as much in discrete, and the results are still out, on whether it is worth it with discrete designs.
When attending university classes in engineering, it is exactly this sort of modeling of transistor behavior that is presented. It can be fascinating, and it can also be confusing.
For example, while attending a engineering class, I was having a cup of coffee with some others attending the class, just before that class started. One fellow said, referring to a fet model that was got the week before: "I understand everything but this factor of 10" I looked at his equations and said: "The factor of 10 is the voltage gain of the stage, or Gm (R)"
I knew this because I had worked in industry as a professional for 5 years before I got to take this class. It is important to realize that the ESSENCE of the design can be lost in the math model, if you are not careful.
I think that is what is being done here. However, I personally encourage different points of view or 'models' of circuitry and devices because each approach can add additional insight of not only how a device works, but how to most effectively and creatively use the device. The pendants here should take note of this.
This is one of the areas that separates engineering from popular electronics. Sometimes it is useful, mostly it is not.
As I said before, in the early days, and even today, sometimes, such as making power amp output stages, you have to realize that BETA is neither infinite or super linear. You also have to look at the graphs showing BETA vs IC and NOTE THE SCALING! Is it semi-log, is it log-log?
Just for fun, convert your favorite output transistor to linear, linear, and see what you get!
This is a real 'eye opener'.
Other times, the BETA is so high and the circuits are so redundant, because it is easy and cheap these days to just add an extra active device or two (or 20) that the effect of BETA is reduced to secondary performance, and Gm becomes useful and necessary to keep an eye on.
There has been a 'revolution' in circuit design since the 1960's primarily due to IC development that uses both differential and current mirror circuitry almost exclusively and virtually a 'cult' seems to be built around this design technique. It IS useful for IC's, but it is difficult and expensive to do as much in discrete, and the results are still out, on whether it is worth it with discrete designs.
When attending university classes in engineering, it is exactly this sort of modeling of transistor behavior that is presented. It can be fascinating, and it can also be confusing.
For example, while attending a engineering class, I was having a cup of coffee with some others attending the class, just before that class started. One fellow said, referring to a fet model that was got the week before: "I understand everything but this factor of 10" I looked at his equations and said: "The factor of 10 is the voltage gain of the stage, or Gm (R)"
I knew this because I had worked in industry as a professional for 5 years before I got to take this class. It is important to realize that the ESSENCE of the design can be lost in the math model, if you are not careful.
I think that is what is being done here. However, I personally encourage different points of view or 'models' of circuitry and devices because each approach can add additional insight of not only how a device works, but how to most effectively and creatively use the device. The pendants here should take note of this.
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