Are voltage and potential the same thing? If not, what is the difference between them? Many electricians confuse voltage and potential, which is not true, and as a qualified electrician, it is important to distinguish between the two.
1. The meaning of voltage and potential.
1. Voltage. Voltage, as the name suggests, can be understood as the pressure on an electric charge. In an electrical circuit, the electric charge is actually the free electron, so the voltage is actually the pressure on the free electrons in the circuit, just like the air pressure refers to the pressure on the atmosphere, and the water pressure refers to the pressure on the water.
With the voltage, the free electrons are able to move directionally under this pressure. As shown in Figure 1-1 below, the number of electrons being pushed in different conductors is different under the same pressure (same voltage), for example, the number of copper is more than that of aluminum. In the case of the same conductor, the greater the pressure (the greater the voltage), the more electrons are moved, which is why the higher the voltage, the greater the current.
Figure 1-1 In the case of an insulator, the electrons cannot move freely because the electrons are firmly bound to the molecule, and the force provided by the voltage is not sufficient to overcome the binding force. Of course, if the voltage is large enough to provide more thrust than the binding force of the electrons, then the electrons will also move, which is called insulation breakdown.
In addition, the generation of the arc is actually because the voltage is large enough, and the pressure it provides is greater than the binding force of the atomic nucleus to the electrons, so the molecules or atoms in the air are ionized, become electrons and ions, and emit a purple arc.
Obviously, voltage can cause electrons to move in a directional way, but this movement is not endless. Not strictly speaking, voltage is actually an electric field, and only when the electrons are in the electric field will they be subjected to the force of voltage. So voltage is a range of quantities, and to be precise, voltage actually refers to the potential difference or potential difference between two points (or two sides).
It's like the height difference on the surface of the earth, along the direction of the gravitational field (i.e., the direction of the perpendicular ground), there is a height difference, we will do free fall, the direction of the gravitational field is like the direction of the electric field, the height difference is like the voltage, and we are like electrons. It's just that the direction of the electric field can be changed, and the direction of the gravitational field on the earth's surface is immutable.
2. Potential. As mentioned above, voltage is also known as potential difference, and the potential difference here is actually the difference between the potential between any two points in the electric field. Obviously, the potential is for a certain point, and the potential is relative, not absolute.
The electric potential is also called the electric potential, it is like the height in the gravitational field mentioned above, for example, I say the height of 5 meters, this 5 meters has two possibilities, one is relative to the surface of the earth, 5 meters above the ground, and the other is relative to the surface on which I am standing, if I stand on the top of the building, then this 5 meters is 5 meters high from the roof. In the same way, the potential is 5 volts, and this 5 volts is also relative, and we have to know that it is a relative point (i.e., a zero potential point, which is assumed to be 0 volts), or the surface of the earth, or a common point ...... the circuit board
Obviously, there is some kind of relationship between potential and voltage, for example, voltage is the potential difference, but this is not enough for us to fully understand the entanglement between the two.
2. The relationship between potential and voltage.
As mentioned above, the presence of voltage is equivalent to the presence of an electric field, and the voltage is a potential difference, that is, there must be points of different potentials in the electric field. In fact, in an electric field, the potential at different points may or may not be the same. The set of these points with the same potential is called an equipotential (potential is a potential) surface. These points with different potentials will have a voltage between any two points.
Let's take a positively charged charge as an example, and the positive charge excites an electric field around it, as shown in Figure 1-2 below.
Figure 1-2 shows the magnitude and direction of the electric field, along the direction of the electric field lines, the potential decreases, but as long as the points are at the same distance from the positive charge, their potentials are equal, and the points are connected to form a circle, as shown in Figure 1-2. The potential of points with the same radius is the same, and the point potential with a larger radius is smaller, for example, the potential of circle 1 is greater than that of circle 2 and circle 3. Since the potentials of different circles are not the same, there is a voltage (potential difference) between different circles, for example, there is a voltage between circles 1 and 2, 2 and 3, and 1 and 3.
Although the potentials of circles with different radii are not the same, the magnitude of their potentials is not absolute, and it depends on the zero potential we have chosen. For example, if we choose circle 2 as the zero potential surface, then the potential of circle 1 is positive, and the potential of circle 3 is negative, if we take the zero potential surface at infinity, then the potential of the circle is positive, but regardless of whether their potential is positive or negative, the potential difference between them (i.e., voltage) is constant.
This is the difference between voltage and potential, and in general, they have something in common and some differences.
The common denominators are as follows:
1. The units are the same, the units of potential and voltage are volts, because the voltage is obtained by subtracting different potentials, so they belong to the same dimension.
2. Both potential and voltage are used to describe the energy of the electric field, because there is a potential or voltage, it can produce force on the electron and do work, the greater the potential or voltage, the greater the work done by the electric field on the electron.
The differences are as follows:
1. The potential is relative, the potential of a certain point is related to the selected zero-potential reference point, and the voltage has nothing to do with the selection of the zero-potential reference point.
2. Voltage is a range value, generally refers to between two points, and potential refers to a point, in other words, once talking about voltage, it must refer to between two points, "what is the voltage at this point" This statement is not correct. But in practice, we often say what is the voltage at a certain point of the live or neutral wire, because we default to the neutral reference point, which in turn is directly grounded. So, we can say what is the voltage at a certain point of the live wire or neutral line, and this voltage is relative to the ground.
At this point, are there any things you don't understand about potential and voltage? Everyone is welcome to leave a comment!
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