What is a fuse? Structure, principle, function, and types of fuses

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Fuses are electrical devices that are commonly used in daily life today. So what is a fuse? What are the specific uses? Let’s find out with us now!

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What is a fuse?

What is a fuse? Fuses are electrical devices used to protect equipment and power grids from short circuits, thereby limiting fire and explosion. More specifically, a fuse is a device used to protect electrical conductors, equipment, and circuits in the event that the power source or circuit is overloaded. The fuse is built into the electrical system. They are directly connected to electrical conductors and electrical devices. Fuse has a simple structure, a small size, and a low cost, so it is widely used in today’s electrical system.

What is a fuse

What is the construction of a fuse?

As mentioned, the construction of the fuse is quite simple. The most important part of a fuse is the fuse, which is connected in series with the two conductors in the circuit. Other parts such as fuse holders, plugs, fuse covers, etc. Specifically, the structure is as follows:

Circuit Breaker

The circuit breaker element is the main part of the fuse; it possesses a very small resistivity value. The circuit breaker element has the function of sensing the value of the passing current. This element is usually made of silver, copper, etc. in the form of wire (circular cross section) or thin tape.

Fuse body

The fuse body must ensure two factors, mechanical strength and thermal conductivity, to withstand sudden changes without being damaged. Therefore, the fuse body is usually made of glass, ceramic, or equivalent materials.

Filling material

Filling material is used to enclose the circuit breaker element in the fuse body. This material has the ability to absorb the energy generated by the arc. At the same time, they must ensure insulation in the event of a circuit break. Therefore, the fill material for fuses is usually granular silicate.


The connector fixes the fuse at the breaker and ensures good electrical contact.

What is a fuse

Working principle of the fuse

In addition to the concept of what a fuse is, this article also provides information on how a fuse works. The fuse works on the principle of self-melting or bending to disconnect from the circuit when the current in the circuit increases. To understand better, let’s analyze the principle of operation of fuses in two cases: when they work at rated current and when a fault occurs.

  • When the circuit is normal: When normal, a rated current flows through the fuse. The heat released does not cause melting. The thermal balance is established without damaging any components of the fuse.
  • When a fault occurs: At this time, the current flowing through is greater than the rated current. The balance on the fuse is destroyed. Thermal energy builds up and melts the circuit breaker of the fuse, opening the circuit at both ends of the fuse.

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Uses of fuses

Fuse for what? This device is used to protect power transmission lines, transformers, electric motors, electrical equipment, control circuits, and lighting circuits.

In an electrical network, a fuse is an important part to protect the system from short circuits. This protects users and property around the electrical system.

Fuses are widely used in household electrical circuits and high-voltage power lines. Disposable fuses are often installed in household appliances such as dryers, coffee machines, etc. However, nowadays fuses are being replaced by Aptomat with more superior features.

What is a fuse

The most popular types of fuses today

1-way electric fuse

This is a small fuse with very stable operation. Since the DC current has a constant value greater than zero, it is difficult to break the circuit, and an arc occurs between the molten conductors. Therefore, the electrodes of the fuse must be far apart. A 1-way fuse provides maximum protection for battery modules and battery packs. It also provides efficient erasure of DC fault lines.

3-phase electrical fuse (AC fuse)

AC fuses are small in size and range from the smallest value to the maximum value 50–60 times per second. This type is specialized for 3-phase electricity, such as low voltage.

Isolation fuse

This type of fuse complies with IEC 947.3. It has protection against overload and short circuit and is widely used in industrial areas.

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The article has answered the question of what a fuse is, its structure, and its operating principle. We hope this information is useful to you. If you need to use electronic components, solder, etc., please contact The Tech for the best advice!

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