I would like to ask you a question about electrical circuits, circuit and electrical appliance experts and masters.

This question is quite interesting.

You can draw this simple circuit diagram, which shows that you have a certain concept of electricity.

Then you should know that the essence of electric current is the directional movement of electrons, right? The direction of current is opposite to the directional movement of electrons. In other words, as shown in the figure, the current flows from the positive terminal of the battery, through the wire, through the bulb, and out again. But electrons move in exactly the opposite direction.

So what causes the directional movement of electrons? That is of course the potential difference, or understood as voltage.

As shown in the figure, when the switch is closed, a potential difference will appear at both ends of the light bulb. Then, electrons will flow from the earth through the wire to the light bulb, and then through the light bulb and then through the wire to the positive electrode of the battery, and then through the battery. flows from the negative pole to the earth. Of course, the opposite direction of electron movement is the current, which should be understandable.

Another key question is: How can the direction of current (or electrons) in the earth be determined? If there is a similar circuit nearby, will it cause interference?

This is another interesting question.

In fact, in the circuit shown in the picture, the electrons in the earth do flow, but they do not flow in the form of an "underground wire" as you might imagine.

Let’s talk about it from an electronic point of view. After the switch is closed, electrons flow from the earth to the light bulb through the wire. At this moment, the electrons from the ground of the light bulb will flow up. This piece of land will show positive electricity, and the electrons will flow back to the earth from the negative electrode of the battery through the circuit, then the battery will be grounded. Shows electronegative properties.

There will be a potential difference between the piece of land showing positive electricity and the land next to it, and the electrons next to it will supplement it, eventually canceling out the piece of land showing negative electricity.

Of course, there is also a speed issue. Will it temporarily cause a certain piece of land to be electropositive or negative? Won't. There is another issue involved here, that is the moving speed of electrons and the moving speed of current.

There will be free electrons in any substance. Under normal circumstances, they move in a disorderly manner. When a potential difference is generated, they will move in a directional manner. This movement is actually very slow. In other words, the electrons move in a disordered manner. Moving one meter in one second is considered fast. But this is the speed at which the electrons are moving, it does not represent the speed of the current. For example, two people stand facing each other, holding both ends of the same wooden stick in their hands. When one of them pushes the wooden stick, the other person can feel it immediately, instead of waiting for the first person's hand to touch it. He will feel it. To put it more simply, the light bulb does not light up until the electrons in the earth flow to the light bulb. This is the speed of current, which is two different concepts from the moving speed of electrons. Different from the speed at which electrons move like crawling, the speed of current is the speed of light (the speed of electric field propagation). It can be seen that although the electrons move very slowly, once the potential difference is formed, each electron will push the previous electron to move in the same direction and at the same speed in the direction of the potential difference, and the speed of this conduction is the speed of light. So there is no need to worry about part or the whole of the earth turning into a big battery.

Also, tell a joke. If we assume that the earth is as big as the entire galaxy and we are still using this kind of circuit, then there will be countless batteries moving at the speed of light in the entire earth. hehe!