Another minor correction (I feel like a schoolmaster!) - electronvolt is a measure of energy, not speed. It is the energy a test charge equal to 1e (=1.6x10^-19 C) gains/loses when you move it through a potential difference of 1V. If the charge is free to move then it will be in the form of kinetic energy, which you can convert to speed if you know the mass of the charge.
It is interesting to compare the drift speed of electrons in a wire in our circuits, with the speed as they hit the anode. The ratio is huge. They are not quite relativistic at the anode, but not too far off!
It is interesting to compare the drift speed of electrons in a wire in our circuits, with the speed as they hit the anode. The ratio is huge. They are not quite relativistic at the anode, but not too far off!
Here is an example of why there is so much confusion.
Ok then why didn't you provide me with a better source of information. You also didn't state it was incorrect.
Yes but if you read my original question you would understand that I am trying to figure out the direction of current flow in a triode. In order to do that we need to define the meaning of AC and DC.
Your brother and cousin being electrical engineers does not constitute proof of your statements.
I agree that people are using AC to define current flowing in a sinusoidal pattern. The problem a sinusoidal pattern can exist DC, at least if you accept the definition of AC and DC in NEETS. I have shown this using a potentiometer in a previous post.
I have read no one state in this thread that the reversal of direct occurs when AC current is mixed with DC.
Your quote above is an example of a conflict.
I completely agree and am not confused on this matter.
Thats because I am using the definition provided by NEETS and other sources. If you use those as the definition of AC and DC you will understand that there is a difference between fluctuating DC and AC from a current flow perspective.
Ok then why didn't you provide me with a better source of information. You also didn't state it was incorrect.
Yes but if you read my original question you would understand that I am trying to figure out the direction of current flow in a triode. In order to do that we need to define the meaning of AC and DC.
Your brother and cousin being electrical engineers does not constitute proof of your statements.
I agree that people are using AC to define current flowing in a sinusoidal pattern. The problem a sinusoidal pattern can exist DC, at least if you accept the definition of AC and DC in NEETS. I have shown this using a potentiometer in a previous post.
I have read no one state in this thread that the reversal of direct occurs when AC current is mixed with DC.
Your quote above is an example of a conflict.
I completely agree and am not confused on this matter.
Thats because I am using the definition provided by NEETS and other sources. If you use those as the definition of AC and DC you will understand that there is a difference between fluctuating DC and AC from a current flow perspective.
btw i read something good but forgot where..
but if one by a electric field coud push the free electrons out of a wire, it would cease to
conduct (but there are physical practicalities making this impossible).
also a vacuum becomes a semiconductor of a unique kind, in a way, if seeded with free electrons (like in a vacuum tube).
i usually try to point out the common thing in apparently stark contrasting things
but if one by a electric field coud push the free electrons out of a wire, it would cease to
conduct (but there are physical practicalities making this impossible).
also a vacuum becomes a semiconductor of a unique kind, in a way, if seeded with free electrons (like in a vacuum tube).
i usually try to point out the common thing in apparently stark contrasting things
Yes, if there was some way to extract the free electrons from a metal it would cease to conduct as all the remaining charged particles are locked into the crystal lattice.
I have not heard of turning a vacuum into a semiconductor, but the vacuum is a strange thing - perhaps much stranger than we can imagine.
I have not heard of turning a vacuum into a semiconductor, but the vacuum is a strange thing - perhaps much stranger than we can imagine.
Of course not
Read again what I wrote... emphasis on the "not reverting". If you want me to re-formulate: "When DC and AC voltages are added, their induced currents sum, which depending on the importance of the DC bias relative to the AC component means that the current will either partially or not all revert direction."And how does it help you to understand anything ? That difference has no practical implications, that's why noone bothers. It's all relative, consider again my post #146. AC in, AC out.
I think the electron in flight in a valve behaves as a classical particle, as it is not fast enough for relativistic corrections to be significant. At the cathode you need to do some quantum mechanics to calculate thermionic emission, although there is a classical version which is not too far out. I'm not certain whether you need quantum mechanics to describe what happens as it hits the anode - you would need QM if it happens to emit a low energy X-ray photon. Once in the anode you need to do the quantum theory of metals.
So I suppose our electron wears different hats at different points in its journey through our valve.
So I suppose our electron wears different hats at different points in its journey through our valve.
By the way, if to speak of an unidirectional current flow we have to forget about electrons, since by definition DC flows from + to -, while electrons flow from - to +. It is incorrect to substitute abstract things by physical ones in this particular case, where all misunderstanding starts from lousy definitions.
Tubes and semiconductors are just variable switches (valves), turning on less or more or in the class t, or d just on and off (pulse width modulated). The resultant is an AC signal in output voltage that through a resister to a reference voltage can be considered or classified as an output AC current. I direct couple DC first and second stages, but AC couple the signal to the outputs due to the voltage level differance, AC couple the drive current required to drive the tubes. clear as mud?
Nothing new. It is very usual when fresh newcomer, or long time sleeper, start similar threads. Kind of entertainment?
Hmm.. Mabe you can assign a quantity for mass if you know the speed? If speed is relative then is kinetic energy relative, and therefore not "contained" in the "particle"...
That's because they're not the same electrons. Vacuum electrons emitted by a cathode, lattice electrons, valence electrons... the list goes on
I guess when you can't divide electrical charge into any smaller units then... voila the electron. They just borrow the property of mass for a little while anyway so how can they be proper "things"?Here's a little thought exercise. How does the charge alone make it through the wire to the terminals of the circuit if there is no load i.e. an open circuit. The potential difference still travels through the conductor to the terminals, but no current flows and no electrons have moved...
well, actually in the wire the electron density then varies,
hence the whole wire potential. actually electrons *will* move if enough. if not by ionizing air or so, the whole wire will move if too much. (electrostatic force)
the wire will desintegrate if even more.
it takes surprisingly few (as it goes) electrons for ridiculous forces, relative to how much electrons there already are in a given wire.
hence the whole wire potential. actually electrons *will* move if enough. if not by ionizing air or so, the whole wire will move if too much. (electrostatic force)
the wire will desintegrate if even more.
it takes surprisingly few (as it goes) electrons for ridiculous forces, relative to how much electrons there already are in a given wire.
I am trying to understand the different current in a tube amp. Some are Just AC, some are Just DC, and some are a combination of both.
Here is image that someone put together to illustrate where the different current are in there schematic. I am not saying that this image has it right or wrong. It just an example.
1. Is the current in my home AC?
2. If the current in mt home is AC is it the same as the AC specified in the image?
3. If it is not the same, then in what way does it differ?
4. If it is not the same, then how does one distinguish which is which in the image?
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