The term insulator refers to a device whose prime function is to ‘insulate’. An insulator is an electrical device that opposes the flow of current in a circuit. This quality of insulators to resist the motion of electrons is of great electrical advantage. They are often used as a protection device in certain circuits with high currents.
In this article, We will discuss what an is Insulator? with its types which are Pin Insulator, Suspension Insulator, Strain Insulator, hackle Insulator, Post Insulator, Stay Insulator, and Disc Insulator. We also discuss their characteristics, applications in real life and what are some of their advantages and disadvantages. Some examples have been added for a better understanding of the concept.
Table of Content
What is Insulator?
Electric Insulators play an important role in Safeguarding us from the potentially harmful Impacts of Electricity. Electron mobility is necessary for the flow of electrical current. The atoms in insulators contain electrons that bond tightly to the material and remain there. As electrons are static, current can’t move through them easily, creating a barrier that keeps electrical shocks from occurring.
Origin of Insulator
Ceramics and glass materials were the earliest devices used for making insulators. Soon it was observed that ceramic material didn’t perform very well with time first non-ceramic insulator was polymer which was introduced to enhance the performance. Telegraph lines were the first electrical systems to put insulators in use. With the advancement, insulators have started to come in various shapes and devices and are made of different materials. There are various insulators like Porcelain, Glass Insulators, Polymer Insulators, Ceramic Insulators, Rubber Insulators, Mica Insulators, Foam Insulators, and Silicone Rubber Insulators, each serving a different purpose.
Types Of Insulators
Insulators can be divided on the basis of their rating:
- Pin Insulator: These insulators are generally used in distribution systems of electrical powers. They can be oriented in vertical or horizontal alignment. These insulators require minimal maintenance. They typically consist of a groove to support the pin or the bolt.
- Suspension Insulator: High-voltage transmission generally employ the use of suspension insulators. Materials like porcelain or glass are used for manufacturing them. The structure consist of a series of discs connected by a metallic link. Any breakage or damage in a single disc can be replaced by a new disc without destroying the whole link.
- Strain Insulator: As suggested by the name these insulators are employed to handle the mechanical strain generated. It is placed in bend or in between corners where strain generated is more. The design is similar to suspension insulator.
- Shackle Insulator: Particularly small in size, these insulators are attached to a cross-arm to support the transmission lines. They are used in overhead distribution and their major characteristic is their U or V shape and their groove to hold the conductor.
- Post Insulator: They are mechanically strong insulators commonly used in substations and indoor places. They have a vertical conductor connected to the top of the insulator.
- Stay Insulator: They are commonly used to support the stay wires and provide additional support. These device are particularly used to protect devices from sudden faults or voltage change.
- Disc Insulator: The characteristic of these insulator is their use in high voltage transmission lines. They are a cost-effective methods with minimum pollutants in environment. The structure consist of several porcelain or glass discs connected in series by metal discs.
Types of Insulator
Working of Insulators
We observe the energy band diagram of an insulator to understand its working:
Energy Bands in Insulator
Valence Band: This is the outermost band and electrons present in this band are valence electrons.
Conduction Band: When free electrons escape from their valence band they get freed from the atom and enter the conduction band.
As seen in the diagram , we have a valence band which consist of the valence electrons and we have a conduction band responsible for conduction. The forbidden energy gap is minimum energy gap which is required to be crossed in order for electrons to transfer from valence band to conduction band.
In order for current to flow, the electrons need to gain sufficient energy to cross the energy gap and enter conduction band after crossing the valence band. Inside an insulator like wood , the energy gap is quite big and therefore it becomes almost impossible to cross this energy barrier. The depletion width is very large and electrons can’t cross this width thereby there is no flow of current.
Unlike insulators, this gap is very low in conductors and electrons can easily cross the barrier causing good electron flow for current generation. Hence, insulators resist the flow of current.
Properties And Characteristics of Insulators
These are some properties of an insulator:
- They have very high electrical resistivity thereby they resist the flow of current in electronic devices and preventing any current leakage.
- They have high thermal resistance meaning they maintain the temperature and other parameters of circuit by preserving the thermal state in circuits.
- They have high mechanical strength. This property is used to talk about how much mechanical stress can they tolerate without breaking. The strength can be designed depending upon the use of insulator.
- They have high dielectric strength which helps them store electrical energy. They also have low permittivity.
- They are often mechanically strong device with high strength.
- Rise in temperature can cause variations in electrical properties of the insulator thereby we need to test resistors.
Solved Examples of Insulators
1. Calculate the density of a 200 ohm resistor of length 5m and unit cross-section area.
Using the formula:
On putting values ρ=40 Kg/m3
2. What is the minimum current in a circuit with 12.5V battery source and maximum value of resistance is 5ohm?
Using Ohms Law
V=I*R Imin=V/Rmax
On putting values, Imin=2.5A
Advantages and Disadvantages of Insulator
There are some list of Advantages and Disadvantages of Insulator given below :
Advantages
There are various advantages of insulators which make them a useful electronic device like:
- They are often used as thermal insulation devices. Due to their insulating properties they are used to control the heat transfer from the device and maintain a certain equilibrium temperature.
- They are often used as safety devices to prevent electrical shocks from circuits. They isolate the conducting element ensuring no sudden shocks to individuals.
- By resisting the flow of current in unintended path direction they help to prevent any wastage of energy. This property is used during communication in transmission lines.
- Due to the good dielectric properties of some insulators, they can be used inside insulators where they act as a storage element and store the electric field.
- Insulators, in general have multiple uses like ceramics in fibre optics, glass, rubber, and plastics are common insulating materials and are employed in various daily use equipments.
Disadvantages
- It become very important to select an insulator with precision keeping in mind its threshold voltage. Insulators have a maximum voltage threshold beyond which they can break down and allow current to flow through.
- Insulating materials are not very adaptive to harsh environments . Due to this, they have short lifespan and may degrade with time reducing their efficiency.
- Synthetic based insulators pose a harm to environment. Like plastic which is a non-degradable insulator can be a serious threat to environment.
- They are not very robust to temperature variations. In extreme temperature conditions ,insulators may show deviation from their properties.
Applications of Insulator
Insulators play a significant role and are very important due to their day-to-day life applications:
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Thermal Insulator: Insulators are often seen for making thermoplastic bottles and fireproof walls and ceilings. This is due to the fact that insulators do not allow the heat to transfer from one point to another.
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Electrical Insulator: Insulators are often used to make motherboard, circuit board and insulation of wires and cables due to the high resistance offered by them which hinders the flow of electron in circuit.
- Sound Insulator: Insulators are often used in acoustics of building and lecture halls because of their noise absorption property. They are good absorbers of noise and help to control the noise level.
Conclusion
In the last, we can summarize by saying that the structure of insulators makes them a perfect device to prevent flow of current. Efficient use of this property can be advantageous to individuals. Dealing with such devices often requires some care . It becomes important to note the parameters like threshold voltage and resistance range of devices while using them in circuits.
Hence insulators are an important class of electronics.
FAQs on Insulator
What are the devices with very high resistivity called?
Insulators are a general class of devices which have very high resistivity thereby resisting the flow of current in a circuit.
What are organic thermal insulators?
Insulators which are made up of organic materials like XPS, and EPS. They contain carbon in the form of polymers forming an organic layer.
What is a semiconductor?
Semiconductor are devices whose conductivity range lies between that of an insulator and a conductor. Heating and doping of semiconductor devices can make them good conductors.