BlogNCERTImportant Topic of Physcis: Insulators

Important Topic of Physcis: Insulators

The electrical insulator is a substance that prevents electric current from flowing freely. The electrons inside the insulator’s atoms are firmly bonded and, therefore, can simply drive. Other substances, semiconductor materials, and conductors conduct electric charges more conveniently. The resistivity of an insulator distinguishes it from semiconductors or conductors; insulators have a higher resistance than semiconductors or conductors. Non-metals are the most common examples. Even insulators contain limited quantities of mobile charges that can convey current hence there is no such thing as a perfect insulator. Furthermore, when a sufficiently high voltage is supplied, the electric field pulls electrons away from atoms, and all insulators turn electrically conductive. An insulator’s breakdown voltage is known as this.

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    A brief outline

    Insulators stabilize and segregate electrical wires in electrical equipment without allowing current to flow through them. Insulation is a bulk insulating substance used to wrap power wires and other equipment. Insulating supports are used to attach electricity generation distribution or power grids to utility poles, and transmission towers are also alluded to as insulators. They bear the weight of the dangling wires while preventing current from flowing through the tower to the ground.

    Insulators are susceptible to electrical breakdown when exposed to an adequate high voltage. When the electric field imposed across an insulating substance exceeds the substance’s threshold breakdown field in any location, the insulator transforms into a conductor, causing a huge rise in current and an electric arc through it. When the electric field in a material is strong enough, free charge carriers are accelerated to a high enough velocity that they knock electrons from atoms as they strike them, ionizing the atoms.

    Important concepts

    Insulator materials

    Glass, porcelain, and composite polymer materials are utilized to make insulators for high-voltage power transmission. Clay, quartz or alumina, and feldspar are used to make porcelain insulators, which are then covered in a smooth glaze to keep water out. When high mechanical strength is required, insulators constructed of porcelain rich in alumina are utilized. The dielectric strength of porcelain is around 4–10 kV/mm. Glass has higher dielectric stability, but it attracts condensation and is difficult to cast without internal stresses in the thick irregular shapes required for insulators. In the late 1960s, some insulator makers abandoned Glass in favor of ceramic materials.

    For various types of insulators, some electric companies have recently begun to switch to polymer composite materials. Composite insulators are less expensive, lighter, and have superior hydrophobic properties. They are appropriate for service in contaminated areas because of this combination. However, unlike Glass and porcelain, these materials still don’t have a long-term established service life.

    10 Examples of insulators


    Because electricity does not flow well through the air, a small gap across circuits can be sufficient to insulate them. Electric fields of extremely high voltage (above 3 million Volts) can, nevertheless, break down air insulation and render it conductive. That’s why a lightning strike, which may have a voltage of up to 300 million Volts, can travel thousands of miles through the atmosphere.


    Ceramic materials composed of brown, red, or white clay are good insulators for electrically conducting materials. Ceramic wire clamps or ceramic coatings are used in most high-voltage systems to insulate wires carrying electric currents. Rather than using glass insulation, many industrial enterprises now use ceramic insulation.


    Cotton is a good insulator when it is dry. It’s often used in fabric tape to protect humans from electrical shock by insulating electrical cables. When cotton gets wet, however, it loses its insulating properties and might become a conductor of electricity.


    Because of their strong carbon bonds, most diamonds are insulators. Blue diamonds are an exception because they contain enough boron to be semiconductors. Diamonds, on the other hand, are not thermal insulators; they transport heat quite well. Many electrical devices, such as generators and electromotors, include diamond insulation.


    Fiberglass is a common type of insulator. Glass fibers and plastic are woven together to form a flat sheet. Fiberglass is commonly tightly woven around high voltage cables and cable conductors if used as electrical insulation. Fiberglass wires are used in many high-temperature devices, such as ovens and furnaces.


    Fiberglass is made up of tiny glass strands. However, Glass can also act as an insulator. Before other materials, such as ceramic and fiberglass, became accessible, Glass was a preferred electrical insulator in phone and power lines.


    Insulating oil, also known as changing oil, has a wide range of applications. Oil-filled converters, high-voltage toggles, circuit breakers, capacitance, and fluorescent bulbs all include this substance. Paper’s inherent cellulose acts as an excellent electrical insulator. Many early electrical equipment was constructed using the paper board, which is made up of multiple layers of dry paper.

    Water in its purest form

    It’s a common misconception that electricity flows through water, but this is not the case. Pure water is an electrical insulator, not a conductor, because it contains no dissolved salts or metals. Impure water, on the other hand, contains elements that carry electricity.


    Because wood contains a lot more space, electricity has a hard time moving through it. However, this is only true for dry wood. When wood is moist, it swells, leaving less free space and making electricity more easily conductible. As a result, wood is rarely employed as a professional insulator.


    Rubber is an attempted electrical insulating material. To protect themselves from electric shocks, most electricians wear rubber gloves, and protective rubber electric mats are frequently found next to fuse boxes and switchboards.

    Insulators have a few uses:

    • Thermal insulators keep heat from moving to start with one area then onto the next. Therefore, they’re utilized to make thermoplastic containers. They’re likewise used to flame-resistant dividers and roofs.
    • Sound insulators are helpful for controlling clamor levels since they ingest sound well. Therefore, we utilize them to make structures and meeting spaces clamor-free.
    • Electrical insulators hinder electron stream and flow stream by means of them. Therefore, we often use them in circuit sheets and high-voltage frameworks. Electric wire and links are additionally covered with them.

    Significance of conductors in NEET exam

    Infinity Learn is here to assist you with accomplishing your maximum capacity by giving you the best educators accessible for every subject. The arrangements have been created as per the latest NEET test. The materials are planned to help understudies reconsider the whole part and perform great on tests. NEET arrangements depend on the latest test standards and standards. It provides understudies with a strong comprehension of the section as well as direct clarifications of the activity issues, with attention to key thoughts. Its motivation is to help students in settling their questions.

    Also read: Semiconductors

    Frequently Asked Questions

    How could you make water more conductive?

    Water is an excellent conductor of electricity. If you want to make it more conductive, you can add salt to it.

    Is it possible to charge insulators?

    By rubbing insulators together, they can be charged. The substance that gives electrons is positively charged, whereas the substance that receives them is negatively charged.

    Mention the important insulator Characteristics?

    The valence electrons in an insulator are closely bound together. They lack the ability to conduct electricity because they lack free electrons. Electrical resistance refers to a material's ability to prevent an electric current from passing through it. Resistivity is the resistance of an insulator per unit cross-sectional area per unit length. The resistivity of insulators is extremely high.

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