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What is the use of fuse in PCB?Circuit board fuses are a type of safety electronic component used to protect circuit boards, and their role is similar to that of ordinary fuses.
Circuit board fuses can play an important role in circuits such as overload protection, short circuit protection, etc. to protect the circuit board and other electronic components. Fuses play a pivotal role in the design and manufacture of PCB circuit boards.
Cirucit board fuses play a very important role in the circuit, it can protect the circuit from overcurrent and overheating damage, thus extending the service life of the circuit. At the same time, fuses also prevent damage to circuits due to short-circuiting, ensuring the safe operation of circuits.
Role of pcb fuses
1. Overload protection: the core role of the fuse is to cut off the power supply when the circuit is overloaded, preventing the wires from overheating and avoiding fires.
2. Short-circuit protection: in the case of short-circuit, the fuse can be quickly blown to prevent the flow of high current through the circuit, to protect the connected equipment from damage.
3. Equipment protection: the fuse can protect expensive electronic equipment from damage and ensure the safe operation of the equipment.
Circuit board fuse application direction:
Fuses and fuses belong to the same safety devices, play the same role, are used to protect the safety of the entire line, the fuse is mainly used for weak products, such as chargers, power adapters, etc., while the fuse is used for products like charging cabinets, photovoltaic energy.
The basic structure of a pcb fuse
General fuse consists of three parts: one is the fuse part, it is the core of the fuse, when the fuse to play the role of cutting off the current, the same class, the same specification fuse fuse, the material should be the same, the geometry should be the same, the resistance value is as small as possible and to be consistent, the most important is the melting characteristics to be consistent. Second, the electrode part, it is the fuse and the circuit connection of the important parts, it must have a good conductivity, should not produce obvious installation contact resistance. Third, the bracket part of the fuse is generally slim and soft, the role of the bracket is to fix the melt and make the three parts of the rigid whole for easy installation, use, it must have good mechanical strength, insulation, heat resistance and flame retardant, should not be used to produce rupture, deformation, combustion and short-circuit phenomena.
What is the rule of thumb for fuses?
The rated current of the circuit board fuse is 25% lower than the rated current of the fuse at 25℃ to avoid ‘I can save the earth’. For example, if a fuse is rated at 10A, it is usually recommended that the operating current should not exceed 7.5A at an ambient temperature of 25°C. Firstly, determine the actual product's rated operating current a, a/0.75 is the fuse's rated current. You can also refer to 1.5-2.0 times of the actual input current of the product to select the rated current of the circuit board fuse. Confirm the withstand voltage: it should be greater than or equal to the effective circuit voltage. The common specification is 250V AC.
Confirmation of electrical characteristics: F (fast-fusing), T (slow-fusing), self-recovery, here need to be combined with the actual application environment for the selection of the product, including surge (lightning strike) immunity Surge, the input inrush current of the relevant indicators. Specifically can be combined with the fuse specifications of the current and time curve for selection, the general switching power supply in the insurance for the slow-melting type.
Confirm the operating temperature range: the actual product application temperature range. The operating temperature range of the fuse should not be less than the actual product application temperature range. Confirmation of package: Combine the volume of the product, process, safety distance, cost, etc., to select the most suitable fuse. Especially the electrical clearance and creepage distance before and after the fuse need to meet the basic insulation. PCB board notes: products that need to do certification, need to print the specifications of the fuse (rated operating voltage and rated operating current) on the PCB, no certification requirements of the product, it is best to synchronise the above as well.
Circuit board fuse as an important protection component of the PCB circuit, play an irreplaceable overload protection and short circuit protection function, to ensure the safe and stable operation of the circuit and equipment. Reasonable selection and design of fuses not only help to extend the life of the circuit, but also effectively prevent equipment damage and safety hazards caused by electrical failure. Following the rules of thumb and selecting the right fuse for the right application is the key to ensuring that the fuse provides the best protection.