When choosing fuses, although they are of the same type, there are still differences. For example, the prices, quality, and parameters of fuses produced by domestic, foreign, and different fuse manufacturers may vary. Especially in terms of price, domestic fuses are cheaper than foreign ones. Why is this? There are also reasons from the fuse manufacturer Answer: At the beginning of design, foreign products have strict regulations from research and development, production, to delivery, basically taking into account many external factors. From the selection of raw materials, manufacturing processes, certification applications, and product pricing, customers have a clear understanding. After the product is completed, it can be tested and sold without any problems, and it will quickly gain customer recognition and trust, resulting in a naturally stable price. Domestic fuses are cheap The positioning of domestic products is to first imitate foreign products and produce them, first re
The disposable slow blow fuse 0402 is a very compact patch fuse with a size of only 1 * 0.5mm, which is the smallest fuse in the patch fuse. The BFS0402 series of BDT-FUSE brand from Baodian Tong can be selected for the 0402 disposable slow blow fuse. This series is a surface mount fast melting thin film fuse. The ultra small package (0402 specification) is very suitable for secondary protection of circuits and is suitable for applications with limited space, such as handheld portable electronic devices. This series is lead-free and meets the requirements of the RoHS directive. The BFS0402 series can correspond to a working current range of 0.25A, 0.375A, 0.5A, 0.75A, 1A, 1.25A, 1.5A, 1.75A, 2A, 2.5A, 3A, 3.5A, 4A, 5A, and a working voltage of 32V. The interruption rating under 32VDC is 35A. BFS0402 provides significant protection for sensitive circuits, and the fuse can activate protection within 5 seconds under a 200% overload condition.
1. The application of self recovery fuse in rechargeable battery pack 1) Problem and Analysis: NICD, NiMH, and Li-ION are commonly used in special protection circuits for mobile phones and computers. The reasons for these battery pack failures are usually: unexpected short circuit between the positive and negative terminals; The charger cannot stop charging a fully charged battery; The polarity of the wrong charger or battery is reversed. Installing the PTC patch series in series in various units of the battery pack can provide overcurrent and over temperature protection for the circuit. 2) Protection requirements: In the event of a malfunction, the voltage of the mobile phone can reach 16V, and the voltage of the computer can reach 24V; Its current can reach 100 amperes. In overcharging conditions, the battery pack needs to be protected against overheating. NiCD batteries cannot exceed 120C, and NiMH and Li Ion batteries cannot exceed 90C. The ultra small package (0402 specific
Normal current flow: It is important for everyone to understand the normal current flow through the patch fuse in the circuit being used. Generally speaking, everyone needs to set a derating amount in advance, and then select according to the following basic principle: the normal current amount must be lower than the product of the rated current and the derating coefficient. Fusing current: According to UL specifications and models, patch fuses should quickly fuse at twice the rated current. But in most cases, in order to ensure stable fusing, we suggest that the fusing current should be greater than 2.5 times the rated current. In addition, when the time of the circuit breaker is important, the judgment must also be made by referring to the circuit breaker performance diagram provided by the manufacturer. Open circuit voltage: The open circuit voltage should usually be selected below the rated voltage. For example, when using a chip fuse with a rated voltage of DC24V in an ACl00
The fuse breaking current of the patch fuse is 1.5 to 2.0 times the rated current. When electrical equipment is in normal use, its fuse will not break. When the current in the circuit exceeds 5 times its rated current, it will automatically break to provide protection. If the fuse melts during normal use of electrical equipment, it indicates that the current in the circuit exceeds the rated current. Therefore, the cause should be immediately investigated. During the installation process of patch fuses, it is necessary to first pull off the switch on the distribution board and cut off the power supply. It is better to use an electric pen to test whether there is power before operating. For fixing screws and washers, copper should be used instead of iron temporarily, as iron can easily rust and lead to poor contact over time. When tightening the fuse, do not use excessive force to prevent the fuse from being flattened and causing a reduction in the cross-sectional area, rated curren
Select the type of fuse based on the electrical load characteristics in the circuit (slow melting or fast melting fuse). Fuses can be divided into slow fuse and fast fuse according to their different fusing characteristics. Fast melting fuses are commonly used in resistive circuits to protect components that are particularly sensitive to current fluctuations; Slow melting fuses are commonly used to quickly disconnect circuits when there is a fault with a large surge current when the circuit status changes. Finally, according to the sensitivity/capacitance circuit (such as the fan motor circuit), it can withstand the impact of surge pulses when switching on and off the machine, and the appropriate fuse type of structure is selected for the actual assembly position where the fuse wire appears. Priority should be given to fuses that occupy little space after installation.