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Fuse: Invisible guardian of circuit safety

  • Source:Network finishing
  • Release on:2025-01-24


In the daily use of electronic devices, security is always an important part that cannot be ignored.When the current is abnormal, overloaded or short -circuited, if there is no effective protection measures, it may not only cause equipment damage, but also cause serious safety accidents such as fire.At this critical moment, a seemingly simple but crucial electronicsComponentIntersectionfuseIt became an invisible guardian of circuit safety.

definition

Fuse (Fuse)Also known as the current fuse, it is an overcurrent protection device.When the current in the circuit exceeds the rated value of the fuse, the fuse will be disconnected due to heat, thereby cutting the circuit to protect the circuit and equipment from damage.The IEC127 standard defines the fuse as "Fuse-Link".

structure

The fuse is generally composed of three main parts:

The melt part:This is the core of the fuse, which plays a role in cutting the current during melting.The material of the same category, the same specifications, the same material, the same geometric size, the sameresistanceThe value is as small as possible and the same is consistent. The most important thing is that the fuse characteristics must be consistent.Household fuses are often made of lead alloys.

Electrical part:There are usually two important parts of the melt and circuit connection.The electrode must have good conductivity, and it should not produce obvious installation contactresistanceEssence

Smedy part:The melt of the fuse is generally slender and soft. The role of the bracket is to fix the melt and make the three parts the whole of rigidity, which is easy to install and use.The bracket must have good mechanical strength, insulation, heat resistance, and flame retardant, and should not occur during use, deformation, combustion, and short circuit.

Working principle

The principle of fuse work is based on the heat generated by current passing the conductor.When the current flows over the fuse, because the fuse itself has a certain amountresistanceIt will generate calories.As time increases, the size of the current and resistance determines the speed generated by heat, and the structure of the fuse and its installation conditions determine the speed of calorie consumption.

The calorie is generated and consumed:If the speed generated by calories is less than the speed of the calorie disappear, the fuse will not melt.If the speed generated by heat is equal to the speed of heat dissipation, the service life of the fuse will be long.If the speed generated by calories is greater than the speed of disappearing heat, the heat generates more and more heat, resulting in a higher temperature.

Following mechanism:When the temperature rises to the fuse melting point, the fuse will be cut off and the circuit will be cut off.This process ensures that the circuit can quickly disconnect under abnormal conditions and prevent the electrical equipment from being damaged by excessive current.

effect

The main role of fuse in the circuit includes:

Overload protection:When the working current of a certain electrical appliance in the circuit exceeds its rated current, the fuse will be disconnected to cut off the circuit to stop the electrical appliances from working to avoid damage to the electrical equipment too much.

Short -circuit protection:When a short -circuit failure appears in the circuit, the current of the circuit will suddenly increase, and the fuse will melt in a short period of time to prevent large currents from continuously flowing through the circuit and play a role in protecting electrical equipment and personal safety.

Isolation protection:The fuse can be used as an electrical isolation switch. When the maintenance or replacement of the electrical appliances is needed, the circuit can be cut off by pulling out the fuse to ensure the operational operation.

Diagnosis failure:When the electrical equipment fails, the fuse of the fuse can indicate the failure of the electrical equipment to quickly diagnose the fault and repair it.

Precautions for Selection

When choosing a fuse, you need to consider the following factors:

Size and shape:The size and shape of the fuse depends mainly on what products users are applied to, and the installation requirements required for the space and current required by the seller to provide the design circuit required by the user.

Volume resistance: The voltage resistance of the fuse needs to be greater than the voltage of the power supply, and leave the appropriate balance to avoid damage to the fuse.

Temperature situation:It is necessary to fully consider the temperature conditions at the location of the fuse, and ensure that the fuse can not be interrupted by mistake within the entire temperature range, and the remaining amount will be more than 25%.

Anti -wave surge ability:Slow fuse is stronger than the anti -wave surge ability of the fuse fuse.Some capacitance or sensual circuits (such as the surge of the swimming), the power input or output part of the power supply is best to use a slow melting fuse.

In summary, although the fuse is small, it plays a pivotal role in the safe operation of electronic equipment.With the development of technology, fuse technology is also constantly improving. For example, the emergence of smart fuses not only has the protection function of traditional fuses, but also provides fault warning through digital signals to further improve the intelligent level of circuit protection.