How to distinguish between an insulator and a conductor, and what is an insulator and a conductor

Whether there are free moving electrons or not, whether they conduct electricity or not.

If two conductors are not insulated from each other and are turned on, it is a larger conductor, which is equivalent to a resistor, not a capacitor. Insulation, a physical term, refers to a safety measure that uses non-conductive substances to isolate or wrap a charged body to protect against electric shock.

Good insulation is the most basic and reliable means to ensure the safe operation of electrical equipment and lines and prevent the occurrence of personal electric shock accidents. Insulation can generally be divided into three categories: gas insulation, liquid insulation, and solid insulation. In practical applications, solid insulation is still the most widely used and reliable insulating substance.

Principle. Under the action of strong electricity, the insulating material may be broken down and lose its insulating properties. Among the above three types of insulating substances, after the gas insulating material is broken down, it can restore its inherent electrical insulation properties by itself once the external factor (strong electric field) is removed; After the solid insulating material is broken down, it irreversibly loses its electrical insulation properties completely.

Therefore, the insulation selection of electrical circuits and equipment must match the voltage level, and must be adapted to the use environment and operating conditions to ensure the safety of insulation.

In addition, due to corrosive gases, vapors, moisture, conductive dust, and mechanical operation, the insulation performance of the insulating material may be reduced or even destroyed. Moreover, the long-term effect of environmental factors such as sunlight and wind and rain can also make the insulating material aging and gradually lose its insulation performance.

The insulation resistance of various lines and equipment under different conditions is roughly as follows:

Under normal circumstances, the low pressure after new installation or overhaul should not be less than 100m; The insulation resistance of low-voltage lines and equipment in operation should not be less than 3mV; The insulation resistance of equipment and circuits in wet occasions should not be lower; The insulation resistance in the control line should generally not be less than 1m, and the insulation resistance of the high-voltage line and equipment should generally not be less than 1000m.

Insulating from each other means that two objects are insulated from each other, and even if there is an electric current passing through them, they are not conductive and are insulators.

A substance that is good at conducting electric current is called a conductor, and a substance that is not good at conducting electric current is called an insulator.

1. There are a large number of charged material particles in the conductor that can be moved by themselves, called carriers. Under the action of the external electric field, the carriers move in a directional way, forming an obviously closed current.

2. Insulator: Electrical insulator is also called dielectric. They have extremely high resistivity, more than 1014 times greater than the resistivity of metals.

Characteristics: Ionized gases can also conduct electricity, and the carriers in them are electrons and positive and negative ions. In general, gases are good insulators.

However, if external causes are used, the gas molecules can be dissociated, so that the ionized gas becomes a conductor. The conductivity of ionized gas has a great relationship with the applied voltage, and is often accompanied by physical processes such as sound generation and luminescence. Ionized gases are often used in the electric light source manufacturing industry.

A conductor is an object that conducts electricity easily, and an object that does not conduct electricity easily is called an insulator. (It is not that objects that can conduct electricity are called conductors, and objects that cannot conduct electricity are called insulators, which is a common mistake made by ordinary people) There are freely moving electrons in metal conductors, and the reason for conducting electricity is free electrons. The resistivity of semiconductors gradually decreases with temperature, and the conductivity is greatly improved, and the reason for conductivity is the holes and electron pairs in the semiconductor.

We usually refer to materials with poor or poor electrical and thermal conductivity, such as diamonds, intraocular crystals, amber, ceramics, rubber, etc., as insulators. Metals such as gold, silver, copper, iron, tin, aluminum, etc., which conduct electricity and heat well, are called conductors. The material between a conductor and an insulator can simply be called a semiconductor.

In metals, some electrons can move freely inside the metal without being bound by the nucleus, and this electron is called free electrons. Metals conduct electricity by relying on free electrons.

Compared with metals and insulators, the discovery of semiconductor materials was the latest, and it was not until the 30s of the 20th century, when the purification technology of materials was improved, that the existence of semiconductors was truly recognized by the academic community.

Objects that easily conduct electricity are called conductors, and objects that do not conduct electricity easily are called insulators. From the perspective of the microstructure of matter, there are a large number of charged particles that can move freely inside the conductor; Inside the insulator, on the other hand, there are few or no charged particles that can move freely.

Metals are the most common type of conductor. Inside the metal, a large number of extranuclear electrons break free from the atom and become electrons that can move freely, called free electrons. Aqueous solutions are also a common type of conductor because in aqueous solutions, many substances are able to ionize and decompose positively charged cations and negatively charged anions.

In this way, there are also a large number of charged particles inside the aqueous solution that can move freely. Insulators such as glass and rock, which are at room temperature, also become conductors when melted at high temperatures. This is because at high temperatures, electrons outside the nucleus gain energy and are able to break free from the bonds of atoms and become free electrons, which sometimes conduct electricity in the form of plasma at high temperatures.

From this, there is no real boundary between a conductor and an insulator, and when conditions change, the original insulator becomes a conductor as well.

There is also a class of substances whose conductivity is between conductors and insulators, and people call it semiconductors. Common semiconductor materials include silicon, germanium, and gallium. Semiconductor materials have many special properties, its resistance is greatly affected by changes in external conditions, people use it to make a variety of electronic devices, in modern technology products have a very wide range of applications.