The electrical circuit or the electric circuit is an interconnection of electrical components to perform a specific function. These circuits use two types of power, one is alternating current and the other is direct current. The AC current is generated by power stations and is used for large devices whereas the DC current is used for batteries, machines, and electrical appliances. When this current is flowing through the devices, the power may increase or decrease suddenly. To protect that circuit breakers or fuses are arranged in series with the components to prevent damage to the whole circuit. Let us see what is the meaning of fuse and circuit breaker, what does a circuit breaker do?
What is a Fuse?
In relation to the electronics, the fuse is an electrical device that provides protection to the electrical circuit from the over current. It is called a sacrificial device because the fuse is a metal strip or a metal wire so whenever there is an overflow of current in the circuit, this strip melts and interrupts the current flow. When the fuse is damaged depending on the type used it must be replaced or rewired.
Some of the reasons for fuse operation are short circuits, device failure, mismatched load, or overload. It is used to remove the power automatically from a faulty device. In recent times, the fuses are sometimes replaced by a special device called circuit breakers. But significantly both share different characteristics.
Fuse – Construction:
We know what is the meaning of fuse, now let us see how it is constructed. A fuse consists of a wire or metal strip that has a small construction compared to all the electrical conductors. These are arranged in series in order to carry the current flowing through the circuit. Due to the current flow the resistance of the element liberates heat. When there is too much flow of current in the circuit then either the fuse will melt directly or the soldered part in the fuse will melt which makes the circuit open.
The fuse elements are made up of desired elements in order to provide stable and predictable characteristics, these elements are copper, zinc, aluminum, silver, or alloys. To increase the heating effect the fuse elements are shaped. The current is divided in between the multiple strips in case of large fuses. To avoid the strain on the fuse these are supported by steel or nichrome wires.
What is the Use of Fuse?
There are several reasons to use the fuse in the circuits, let us see what are they:
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These are used as safety for the electrical circuits.
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They are less costly.
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The reliability of the fuses is very good.
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As the age of the fuse increases, its speed remains the same.
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There is no necessary to maintain the fuse often.
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To have a high interrupting capacity it is not necessary to pay for the high premiums.
What is Circuit Breaker?
Circuit breakers are automatically operated switches that are specially designed to protect the circuits from damage. As its basic function is the same as that of the fuse it is not necessary to replace the circuit breaker with a new one, instead, they can reset by themselves or manually to continue performing its operation. The size may vary as they are made to protect the small household appliances from the large sitch gears that pass high voltage. The circuit breaker that removes the power from the faulty device is also abbreviated as OPCD – Over Current Protective Device.
Circuit Breaker – Operation
Let us see what do circuit breakers do? The circuit breaker first detects the fault. The detection in the low voltage circuit is done by itself. In the case of high voltage devices, a separate protective relay is been arranged, and hence for the operation of these relays, an extra power supply is required. Once the fault is detected, the circuit must open by removing the connection in between the contacts and this is done by the energy stored in the circuit breaker. The stored energy is such as the battery, or compressed air or the thermal expansion, or magnetic field. Once the contacts are removed, the small or miniature devices are discarded and in the case of high voltage circuit breakers or power circuit breakers, the contacts can be replaceable.
We have seen what is a fuse and a circuit breaker. Now let us look at the difference between,
Fuse vs Circuit Breaker
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Fuse |
Circuit Breaker |
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Its working principle is based on the electrical or thermal properties of the conducting materials. |
It works on the electromagnetism or switching principle. |
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In case of overload, an indication is not provided. |
An indication is provided whenever there is an overload. |
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These are used only once. |
It can be used several times. |
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The detection and interruption are done by the fuse itself. |
It performs only the interruption operation whereas the detection is done relay system. |
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Perform automatically. |
These perform manually or automatically. |
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It has a low breaking capacity. |
High breaking capacity. |
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It has a low cost. |
It has a high cost. |
Types of Circuit Breaker:
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Air circuit breaker.
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Molded case circuit breaker.
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Miniature circuit breaker.
Conclusion:
In the case of the power connection, the flow of electricity takes place through the circuit box. The fuse or the circuit breaker performs the same operation, they help the devices to protect the circuit from damage and they act as a switch. These can be operated manually or automatically. Once these are operated on the faulty devices they can either be replaced or sometimes they can reset themselves to continue the operation.