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It all depends on,conceptually, what you are trying to do in regards to the utilization of power. For instance, most modern automobiles take the negative terminal from the battery and attach to the chassis. Why? The voltage drop of the big ass chassis is less than it is on a #14 wire. In this case, the designers want to control the return current via fuses and switches. With the negative side of the battery attached to the chassis, more electrons are available to the various devices, scattered all over the vehicle, to be powered, and the control is achieved on the return, not the source.
In older tube (Valve) and early solid state equipment like radios and Hi-Fi equipment, the negative side of the power supply was traditionally connected to the chassis of the device, and control of the circuitry was left to the positive return current that finds its way back to the power supply. Again, the designer wanted the chassis, a larger conductor than 18 gauge wire used on the positive side, to have as many electrons a possible available to the various devices in the equipment.
This was done on purpose, not on a whim or a coin toss.
In the telecommunications industry, at switching centers, the opposite is true. These designers, for well over a hundred years, decided that they wanted to place control on the source of electrons instead of on the return path. So in these switching centers, these thousand amp battery supplies ground the positive terminals to the office ground bar (Chassis). These -48 volt battery plants (actually, these days it is -52 volts) are what power all of the switches and routers in the center. This is not always the case in remote sites like a cell location, which also run on batteries, there it can be mixed or negative ground, depending on the equipment. Some radio transmission equipment that attaches to exterior antennas like negative grounds. I'm not sure, but I think it has to do with keeping lighting away from the equipment.
Today, many circuits function on very low voltages compared to those in the past, and it does not matter as the current requirements on many devices are so low. So unless you are talking about battery chargers or power amplifiers, you can do pretty much set your reference (that's what we are actually talking about here) to any thing you want.
So, again, it depends on what you want to do conceptually, when decisions are made regarding circuit design. The Electron theory is in tact, and the Hole theory can work for you if that is what you need. Do what works best for the concept of the design.
Rick -
With the negative side of the battery attached to the chassis, more electrons are available to the various devices, scattered all over the vehicle, to be powered, and the control is achieved on the return, not the source.
I think you have a big conceptual misunderstanding here. It is irrelevant from an electrical point of view whether the positive side of the battery or the negative side is attached to the chassis. Everything will work just the same either way. There is no "source" or "return" in a circuit. -
+1
(Left me scratching my head, that one did.) -
Either way, you are abstracting. It is not as if electronic designers regularly watch a line of electrons flow from the (-) end to the (+) end. The electron flow or the current flow is as abstract as whether we use C for current and measure it Pma, verses I for current and measure it in Amp. The math stays the same.
Switching, even if feasible, is not going to make it easier to develop better electronics. It won't make a bit of difference at all. Electronic Engineers who fails to grasp this simple abstraction is not going to have any kind of a career in electronics anyhow. -
With the negative side of the battery attached to the chassis, more electrons are available to the various devices, scattered all over the vehicle, to be powered, and the control is achieved on the return, not the source.
I think you have a big conceptual misunderstanding here. It is irrelevant from an electrical point of view whether the positive side of the battery or the negative side is attached to the chassis. Everything will work just the same either way. There is no "source" or "return" in a circuit.
If you accept the theory that electrons flow from negative to positive (Electron Theory) then there is no misunderstanding on my part. If you connect a conductor to the metal frame of a vehicle, the size of which is tens to hundreds of times larger than a 4 mm wire, you must agree that the voltage drop from one end of the vehicle frame to the other will be less than it will be on the 4 mm wire, especially as current requirements increase. It is. Not by very much, but it is. If the voltage drop is less on the frame, then the source of the power (Electrons), (Electron theory) available must be higher than it would be on the 4 mm wire.
If you are not aware of Source and Return when it comes to power circuits, you may want to investigate those terms, as they are used in large battery plant designs. Some times "Battery" is used instead of "Source". Sometimes "Ground" is used instead of "Return". You may not use these terms on your Arduino project, but they do exist in DC power plant design.
As I said earlier, the designers didn't just flip a coin to decide on the best way to distribute power in a particular instance. The Physicists looked at the concept, saw what work needed to be done, and made a decision based on the known science. -
If you connect a conductor to the metal frame of a vehicle, the size of which is tens to hundreds of times larger than a 4 mm wire, you must agree that the voltage drop from one end of the vehicle frame to the other will be less than it will be on the 4 mm wire, especially as current requirements increase. It is. Not by very much, but it is. If the voltage drop is less on the frame, then the source of the power (Electrons), (Electron theory) available must be higher than it would be on the 4 mm wire.
Do I even bother pointing out the GLARING HOLE in this argument? -
... or would I just be feeding a troll?
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I can assure you that I am no troll. Hole. Cute.
When I was in college in the 1960s, the Electron Theory was pretty much considered settled science. It was the way we were taught. In the late sixties, the Hole Theory started to gain some acceptance as a "Out of the Box" way to explain certain things in a different way that some found easier to understand, without getting too deep into the physics. And it made for a logical way to explain these new fangeld things like solid state (transistor) gates. As someone said earlier, it doesn't matter either way, the math works out the same.
As the Electron Theory was considered settled science, many engineers used this settled science deciding the proper way to efficiently deploy electrical devices. Therefore in certain disciplines, certain methods were deemed proper. In the automobile example, the reason one of the battery conductors was connected to the chassis was that is was an effective method to partially distribute power. As the settled science at the time was the Electron Theory, (current flows from negative to positive), the negative side of the battery was chosen to be connected to the chassis. Why? Since it was the largest electrical conductor in the vehicle, as more devices that required power (lights, turn signals, radios, starters, fans) would suffer less voltage drop as the current requirements increased when one side of these devices were connected to the chassis, and these devices were used at the same time. And it saved a lot of money because you only needed to run one conductor to a specific device as the other conductor was already there at the chassis. Of course it works the other way as well, but that method (the Hole Theory) was not considered settled science at the time, in power distribution circles. And when decisions are made like this in any industry, you needed to have the settled science on your side or you would not last very long, because the bean counters didn't care, they were only concerned with consensus of the scientific community. If something went wrong, your behind was covered because you agreed with the consensus of the scientific community.
I spent 37 years as a power engineer before I retired. Today I am a hobbyist, mainly working on old tube amplifiers.
The question was asked "Why not change conventional current (Hole) to electron current? (Theory)" I was providing information on the history of why the decisions that were made, were made. And in certain disciplines, the Electron Theory is the preferred method used to explain the operation of specific devices. So the question is not really valid as I believe the OP was under the impression that the "Conventional Current" method is the only way that these concepts are explained, and it is not.
Rick -
[Just for the sake of anyone else reading this discussion, who may be in danger of being confused or misled]:
Current flows in loops, from the battery, through a conductor, then through the load, then back to the battery via another conductor.
Each conductor has resistance, and the resistance of a car body is indeed likely to be less than that of a length of wire, but the choice to connect it to the terminal marked '-' rather than the terminal marked '+' doesn't make any difference whatsoever to the voltage across the load.
Why? Because the load, the wire and the car body are all electrically in series. The voltage across the load equals the voltage across the battery, minus the voltage drop across the wire, minus the voltage drop across the car body.
If the battery voltage is exactly 12.0V, then in the "negative earth" case the voltages at the terminals of a moderate load (measured with respect to the '-' terminal of the battery) might be +11.5V and +0.1V, and in the "positive earth" case they'd be +11.9V and +0.5V.
In both cases, the voltage across the load is 11.4V. This figure is exactly the same, regardless of which part of the loop is formed by the car body and which part of the loop is formed by the wire.Quotebecause the bean counters didn't care, they were only concerned with consensus of the scientific community
I've never once heard of any case in which bean counters know, or care, about the consensus of the scientific community.Quotethen the source of the power (Electrons)
Noooooo!!!!
Electrons are not the source of any power; the chemical reaction in the battery is.QuoteIn the late sixties, the Hole Theory started to gain some acceptance as a "Out of the Box" way to explain certain things in a different way that some found easier to understand, without getting too deep into the physics
For what it's worth, a 'hole' isn't quite the same thing as the absence of en electron. In a semiconductor, a 'hole' is (specifically) the absence of an electron in one of the inner orbits around the nucleus; electrons in this band are more tightly bound to the nucleus than the 'free' electrons which carry current more like those in a metallic conductor.
The different energy levels are important. Conduction by holes is less efficient because of that tighter binding between electrons and nuclei in the inner orbits; it takes more energy to strip an electron from its nucleus. This is why P-channel transistors are generally inferior to their N-channel counterparts.
Under the right conditions (which are to do with the respective energy levels of electrons and holes, and the 'band gap' of the material in question), electrons and holes can recombine, and the energy which was originally put into the electron to strip it from its nucleus is released in the form of a photon of light. This is how an LED works.
Conduction by holes doesn't happen in metals, though. They're a semiconductor phenomenon.
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Quote
because the bean counters didn't care, they were only concerned with consensus of the scientific community
I've never once heard of any case in which bean counters know, or care, about the consensus of the scientific community.
You and I live in different worlds! Where I live, bean counters want 5 nines, and if you could not provide it, they want to know if you are using standard norms(scientific consensus), and if not why?
Electrons are not the source of any power; the chemical reaction in the battery is.
In this discussion, a battery was used as a power source. A generator or a solar panel could have been used as well.QuoteIn the late sixties, the Hole Theory started to gain some acceptance as a "Out of the Box" way to explain certain things in a different way that some found easier to understand, without getting too deep into the physics
For what it's worth, a 'hole' isn't quite the same thing as the absence of en electron. In a semiconductor, a 'hole' is (specifically) the absence of an electron in one of the inner orbits around the nucleus; electrons in this band are more tightly bound to the nucleus than the 'free' electrons which carry current more like those in a metallic conductor.
The different energy levels are important. Conduction by holes is less efficient because of that tighter binding between electrons and nuclei in the inner orbits; it takes more energy to strip an electron from its nucleus. This is why P-channel transistors are generally inferior to their N-channel counterparts.
Under the right conditions (which are to do with the respective energy levels of electrons and holes, and the 'band gap' of the material in question), electrons and holes can recombine, and the energy which was originally put into the electron to strip it from its nucleus is released in the form of a photon of light. This is how an LED works.
Conduction by holes doesn't happen in metals, though. They're a semiconductor phenomenon.
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Semiconductors are not everything! I was talking about power distribution and how it is/was referenced. -
... and you still didn't get it right.
Each conductor has resistance, and the resistance of a car body is indeed likely to be less than that of a length of wire, but the choice to connect it to the terminal marked '-' rather than the terminal marked '+' doesn't make any difference whatsoever to the voltage across the load.
Why? Because the load, the wire and the car body are all electrically in series.
Exactly.
But you missed mentioning one - rather critical (especially lethal to your argument) - part of the circuit:QuoteThe voltage across the load equals the voltage across the battery, minus the voltage drop across the wire, minus the voltage drop across the car body.
A point, I might add, you completely ignored in your response to AndyC_772's post. -
We don't want to change to have the ground on the top. Because with the ground on the top, than we than need to walk our hands. That would be ridiculous now, wouldn't it? So that is why the GND is on the bottom, and current flows that way.
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Sweden day after switching from left to right hand traffic
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Short-form answer: Physics works at both the macroscopic and microscopic level.
"Current" is a macroscopic phenomenon, and can flow in either direction across a specific boundary. Polarity definitions (on current, voltage, etc.) must be consistent and agreed to make useful calculations.
"Electrons" are a microscopic phenomenon. Charge carriers forming current can be electrons with negative charge, holes with positive charge, protons with positive charge, etc. The product of charge density (scalar) times velocity (vector) times boundary area gives current density (vector).
The accepted definitions of polarity are experimentally consistent, and there is no need to change them on a whim. -
Short-form answer: Physics works at both the macroscopic and microscopic level.
To be honest, I never seen an electron. I really don't care which way they flow. So it is not proper physical model, and physicist have headaches. If I connect a battery the right way, the current will flow the right way, and the circuit will work. It takes an engineering brain to comprehend that this is a compromise, the very thing that an engineer will need to do every single day.
"Current" is a macroscopic phenomenon, and can flow in either direction across a specific boundary. Polarity definitions (on current, voltage, etc.) must be consistent and agreed to make useful calculations.
"Electrons" are a microscopic phenomenon. Charge carriers forming current can be electrons with negative charge, holes with positive charge, protons with positive charge, etc. The product of charge density (scalar) times velocity (vector) times boundary area gives current density (vector).
The accepted definitions of polarity are experimentally consistent, and there is no need to change them on a whim. -
In my physics education, I have "sensed" (if not "seen") electrons (and other charged particles).
1. Millikan oil-drop experiment: measured discrete changes in charge on small oil drops. (At the University of Chicago, I used antique equipment originally built for Professor Robert Millikan himself.)
2. Shot noise in vacuum diodes: statistics of individual electrons vs. diode current.
3. Beta decay: counting individual electrons emitted by nuclear disintegration.
4. Ion beams. Counting individual protons that have been accelerated through a vacuum to a detector.
Of course, one does not see the electrons involved in current through a copper wire. The current is not single electrons zinging down the wire, but a slight tendency for each of a zillion electrons to move in the appropriate direction. -
In my physics education, I have "sensed" (if not "seen") electrons (and other charged particles).
You poor deprived soul. Buy me a beer and I'll post you some
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In my physics education, I have "sensed" (if not "seen") electrons (and other charged particles).
1. Millikan oil-drop experiment: measured discrete changes in charge on small oil drops. (At the University of Chicago, I used antique equipment originally built for Professor Robert Millikan himself.)
2. Shot noise in vacuum diodes: statistics of individual electrons vs. diode current.
3. Beta decay: counting individual electrons emitted by nuclear disintegration.
4. Ion beams. Counting individual protons that have been accelerated through a vacuum to a detector.
Of course, one does not see the electrons involved in current through a copper wire. The current is not single electrons zinging down the wire, but a slight tendency for each of a zillion electrons to move in the appropriate direction.
And you can do related experiments to count photons, while other well known experiments prove their wave nature. At least when I was taking quantum physics the same equations applied to both electrons and photons, but mass and hence wavelength differences make the observables different. We probably don't really understand the fundamental nature of our universe, we just have models that work pretty well under a variety of controlled conditions. Why don't we just argue how many angels can stand on the head of a pin? Has just as much value. Actually it is fun to visualize moving the internet back to the time when they were argueing about angels and pin heads. The flame wars would have been intense. -
This was not the official dogma I learned, but I decided that "wave" and "particle" are mathematical descriptions. When describing reality, one or the other is more appropriate, depending on what is being observed, to calculate the result. The calculated results can be very accurate when compared with experiment.
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I swear guys, I've shined a flashlight inside every vacuum tube I've looked at! Nothing but vacuum in there! Electrons don't exist!
Tim -
... and you still didn't get it right.
Each conductor has resistance, and the resistance of a car body is indeed likely to be less than that of a length of wire, but the choice to connect it to the terminal marked '-' rather than the terminal marked '+' doesn't make any difference whatsoever to the voltage across the load.
Why? Because the load, the wire and the car body are all electrically in series.
Exactly.
But you missed mentioning one - rather critical (especially lethal to your argument) - part of the circuit:QuoteThe voltage across the load equals the voltage across the battery, minus the voltage drop across the wire, minus the voltage drop across the car body.
A point, I might add, you completely ignored in your response to AndyC_772's post.
Brumby my friend, I didn't ignore Andy's quote. I agreed with everything that he stated that I didn't quote. What I did quote, were the issues that I responded to.
I also agree with your statement "The voltage across the load equals the voltage across the battery, minus the voltage drop across the wire, minus the voltage drop across the car body.
[/quote]
My point was that the VD across the wire will be different than the VD across the car body, because the wire will have a higher resistance than the car body.
But you got me to question my theory, so I will create an experiment, using a large wire, say a number 2, and a smaller wire, say a number 14, along with an incandescent bulb, and attempt my measurements across those two wires with current flowing. Number 14 copper wire has a resistance of .253 ohms per hundred feet. Number 2 copper wire has a resistance of .016 ohms per hundred feet. I will try to create these parameters on my bench to see if I can measure a difference. If there is no difference then I will take back what I said. If there is a difference, perhaps we can have another discussion.
Best regards.
Rick -
Your statement:
... and attempt my measurements across those two wires with current flowing.
is vague.
If you are going to measure the potential difference from one and of wire 'A' to the other and the potential difference from one and of wire 'B' to the other, then your experiment is pointless. The answers can be given using Kirchhoff and Ohm's laws.
What really matters is the voltage across the load.
But your fundamental premise is simply incorrect, so any experimental processes have to be questioned as to how relevant they are in demonstrating the claims.
If there is no clear relevance, then trying to apply some quantitative results is nothing more than useless - unless the intention is to try and bamboozle. Either way, nothing is proven. -
Your statement:
... and attempt my measurements across those two wires with current flowing.
is vague.
If you are going to measure the potential difference from one and of wire 'A' to the other and the potential difference from one and of wire 'B' to the other, then your experiment is pointless. The answers can be given using Kirchhoff and Ohm's laws.
What really matters is the voltage across the load.
But your fundamental premise is simply incorrect, so any experimental processes have to be questioned as to how relevant they are in demonstrating the claims.
If there is no clear relevance, then trying to apply some quantitative results is nothing more than useless - unless the intention is to try and bamboozle. Either way, nothing is proven.
I am not trying to bamboozle or troll anyone. I would get no pleasure from that, actions like that are juvenile.
The premise of the experiment is that if you use one large conductor and many smaller conductors for multiple devices that are used at the same time, like in an automobile, that the VD would be different on the smaller conductor than on the larger conductor. And that premise is why that particular power distribution system was decided upon for that application, not to mention that it saves a lot on power wiring. Again, you need to understand the concept for what you are trying to accomplish.
I have been nothing but civil and I don't appreciate being called a troll for having a technical conversation about circuit operation. I have not addressed you in that kind of disrespectful fashion and if you are saying that I am intentionally trying to trick or fool others, you are dead wrong.
Again, there is a reason that the application in the automobile was designed the way that it was, and you have not provided any other explanation as to why that design was deployed that way. At this point the voltage across the load is not the concern. The question is about the distribution of power to multiple devices operating at the same time and what is the most efficient way to provide that distribution.
Rick
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OK - Lets get something clear.
The whole origin of any 'confrontation' stems from your claim that choosing the polarity of the chassis connection was a deliberate choice, based on good reason - that a negative connected chassis provided tangible benefits over a positive connected one.
What others who have challenged this claim (including myself) is that, in practice, it does not matter what polarity is used. Any circuit under consideration will have the same path - passing through a section of the chassis, the load and a wire - no matter which direction the electrons flow.
Do you agree that this is an accurate statement? -
The premise of the experiment is that if you use one large conductor and many smaller conductors for multiple devices that are used at the same time, like in an automobile, that the VD would be different on the smaller conductor than on the larger conductor.
This is not a premise, this is a predictable fact. It follows from the simple application of Ohm's law.
However, that's not what you said. You said that making the big conductor negative would produce different results from making the big conductor positive. It wouldn't.