Mass, Ground, Zero Potential: Understanding Electronic Circuits, Car Body Connections

Hello.

My question may seem trivial and quite "stupid", but I am not able to find the answer to it on the internet.

Well, the point is that I know that ground is where the potential is zero, so the voltage is zero volts. I read that physically it can be any element that conducts electricity but has a zero potential, such as a bulb screw or a car body.

During the electronics classes in college, we connected the masses with each other with a resistance-free cable. On one page I found a definition that the mass is simply a simplification of the diagram to make it more readable and that we simply connect all the grounds together and connect the whole to ground. It is understandable.

So I do not understand how it relates to this car body. According to this definition, the mass may even be, say, a piece of lamina. How does it relate to connecting the masses with a resistance-free cable?

Another question is about the zero potential. I quickly drew a fragment of the circuit. If, as in class, we connect the ground wires with each other, will there still be a zero potential at this point?

Thank you and best regards.

You write about some non-resistance cable is some kind of superconductor. In physics, every conductor has some resistance. Can you explain why this cable is non-resistive?
Perhaps, materials from Area 51 were used to make this cable

Hello.
The ground GND is the reference point for the remainder of the electrical circuit.
The use of this term improves the readability of electrical diagrams.
These points are physically connected to each other.

Meph1k wrote:

During the electronics classes in college, we connected the masses with each other with a resistance-free cable.

Of course, you connected in your thoughts, because in practice resistance-free cables do not exist ;)

Meph1k wrote:

So I do not understand how it relates to this car body. According to this definition, the mass may even be, say, a piece of lamina.

The car body is just a piece of the plate (a bit larger) to which all the points that we consider to be connected to ground are connected - negative battery pole, negative alternator terminal, negative starter pole, one transport of most bulbs, etc.

Meph1k wrote:

During the electronics classes in college, we connected the masses with each other with a resistance-free cable

You study electronics and are you not ashamed to ask such questions?

A little about the issue of mass has already been written in various electronic literature.
https://obrazki.elektroda.pl/9395736400_1440824081.jpg
Sometimes the mass also acts as a screen. It was common, for example, in old tube amplifier designs.

mikstu2 wrote:

Sometimes the mass also acts as a screen. It was common, for example, in old tube amplifier designs.

In modern times as well

Freddy wrote:

Meph1k wrote:

During the electronics classes in college, we connected the masses with each other with a resistance-free cable

You study electronics and are you not ashamed to ask such questions?

Well, I am very intrigued by this cable without resistance. Will this student explain anything about it? Maybe at this university they actually have access to technology
from Area 51.

The most important thing is mass contractual reference point, we assume assuming that it has 0V because it's a very convenient assumption
Therefore, the mass does not have to be connected to any sheet metal, neither to the ground, nor to the negative of the power source, if you assume that the plus of the battery is the mass, it will be your choice, some old cars had that, in systems with germanium transistors, plus was usually taken as a mass .

In the car or in the plane, the mass is not connected to the ground, and if the plane is hit by lightning, even if it is hundreds of kV in relation to the ground, the mass in the plane is still 0V, because that's what we assumed.

Earthing is used for safety reasons, often the ground is connected to the protective conductor of the network.

The car body in the car acts as a return conductor and, by the way, is a 0V reference potential.

In the diagrams, the mass symbol improves readability - it eliminates all the lines with which the masses would have to be connected, and the power supply is also marked with the appropriate symbol (circle, old or thin horizontal line with a description) for the same reason.

Thanks to everyone who replied normally and to the point.

For those who are interested: I am not studying electronics, but computer science, third semester.
There was always only "short circuit to ground", "ground is zero potential", "we connect the masses together" etc. Never a factual explanation of what it is.

And unfortunately we do not have access to materials from zone 51.

I am aware that there are no perfect elements. Just as a voltmeter has no infinite resistance, an ammeter has no zero, and we will not buy a resistor that is exactly 1 kilo ohm.

Some people may have forgotten that in electronics classes, the assumption is that elements are ideal when it comes to counting, for example, the transmittance of an op-amp. Therefore, I wrote "cable without resistance" because we never take into account that the cable has any resistance at all. Now we have an electronics laboratory, where, of course, we no longer accept it, but the exam will be made of perfect elements .

I can see what some of them say, but it is often true what they write about the electrode in the excavation. Some people are too self-righteous.

Thanks again to everyone for clarifying the topic.
Kind regards.

@ Meph1k If you like such nonsense, maybe change your direction or your university.

Meph1k wrote:

And unfortunately we do not have access to materials from zone 51.

After your statements, it appears that it is probably so.

Meph1k wrote:

Some people may have forgotten that in electronics classes, the assumption is that elements are ideal when it comes to counting, for example, the transmittance of an op-amp. Therefore, I wrote "cable without resistance" because we never take into account that the cable has any resistance at all. Now we have an electronics laboratory, where, of course, we no longer accept it, but the exam will be made of perfect elements.

And that's why there are then ... and not engineers. Then one comes to the store in part and says they taught him that.
Complete paranoia.
There are no perfect elements, and even during studies they teach and show what are the equivalent diagrams of coils, capacitors, resistors, etc., etc., because there are no perfect ones.

Freddy wrote:

There are no perfect elements, and even during studies they teach and show what are the equivalent diagrams of coils, capacitors, resistors, etc., etc., because there are no perfect ones.

It depends on what studies, because I suspect it is probably not in IT. I met IT specialists after graduation, who had almost no idea about electronics, or if it was very pale.

Meph1k wrote:

Therefore, I wrote "cable without resistance" because we never take into account that the cable has any resistance at all.

Therefore, it is better to use the term "wire with negligible resistance".
And a cable is a cable, in electronics, cables are very rare, it is better to keep this term for a specific type of cable.

mikstu2 wrote:

It depends on what studies, because I suspect it is probably not in IT. I met IT specialists after graduation, who had almost no idea about electronics, or if it was very pale.

What is the difference after what studies.
Electronics and the principles of physics are the same all over the world.