I hold current I hold, high non operating current (maintenance current), refers to the high current that PPTC always maintains its low resistance state at the specified ambient temperature (priority 25 ℃). I hold: maintain current; V max: withstand high voltage; T trip: specifies the large action time under the current; R: Zero power resistance measured at a certain temperature; I trip: action current; I max: The maximum current that can be withstood; P d: steady-state power consumption in high resistance state; R 1max.: The high resistance value measured at room temperature after one hour of action or soldering. Let's take a look at the internal structure of the device, as shown in Figure 4. Place the test sample in a specified temperature and condition test box, connect the PPTC to a constant current or constant voltage source, and preset the current value to the specified I hold, with the voltage limited to 90% of V max. After the specified time in the detailed specifi
Chip fuse is a relatively high-tech new variety in the small fuse industry. Chip fuse can be divided into disposable chip fuse and chip self recovery fuse. Disposable chip fuse, also known as chip current fuse, needs to be replaced after protection, and after self recovery fuse protection, power is cut off, it can be restored on its own and can be reused. The disposable patch current fuses can be divided into the following models based on size and performance: (1) According to size, products can be divided into: 0402, 0603, 1206241061251032. (2) According to performance, products can be divided into three types: fast melting, slow melting, and enhanced melting heat energy. The SMD fuse quick blow series is suitable for protecting important components that quickly respond in circuits, and is generally used in situations where surge currents rarely occur; The slow fuse series is suitable for situations where large surge currents often occur in circuits; The enhanced melting heat e
1. According to the protection form: overcurrent protection and overheating protection. The fuse used for overcurrent protection is commonly referred to as a fuse (also known as a current limiting fuse). Fuses used for overheating protection are generally referred to as "temperature fuses". Temperature fuses are also divided into low melting point alloy type, temperature sensing contact type, and memory alloy type, etc. Temperature fuses are used to protect against excessive temperature changes in heating appliances or Yi Ge heating appliances, and their working principle is different from "current limiting fuses" The melting of temperature fuse melts is independent of the operating current of the circuit. 2. According to the scope of use: power fuse, machine tool fuse, electrical instrument fuse (electronic fuse), automotive fuse. 3. According to the rated voltage level: high-voltage fuse, low positive fuse, and safety voltage fuse. 4. According to breaking capacity: high break
1. Determine the following parameters of the circuit: A Large working environment temperature b Standard working current c Maximum working voltage (Umax) d Maximum fault current (Imax) 2. Select self restoring fuse components that can adapt to the ambient temperature and standard operating current of the circuit Use a temperature reduction {ambient temperature (℃) working current (A)} table and select the temperature that best matches the ambient temperature of the circuit. Browse this column to view values that are equal to or greater than the standard operating current of the circuit. 3. Compare the high electrical rating of the selected component with the high operating voltage and fault current of the circuit Use the electrical characteristic table to verify whether the components you selected in step 2 will use the high operating voltage and fault current of the circuit. Check the high operating voltage and high fault current of the device. Ensure that Umax and Imax are g
1. Rated voltage Rated voltage refers to the high voltage that can be withstood after the self recovery fuse is disconnected. The voltage borne by both ends of a self restoring fuse during the connection period is far less than its rated voltage. When selecting a self restoring fuse, it is generally required that its rated voltage be greater than the effective circuit voltage. 2. Rated current The rated current is the high current that a self restoring fuse can operate for a long time. Assuming the protection current is Ir and the rated current of the self recovery fuse should be In, both should meet the following conditions: In=Ir/(fo * f1), where fo is the reduction rate for self recovery fuses of different specifications. For self recovery fuses of ICE specifications, no reduction rate can be added, that is, fo=1. For self recovery fuses of UL specifications, the reduction rate is fo=0.75. To consider the reduction rate after considering temperature, the higher the ambient te
1. Voltage Ratings: The voltage rating of the fuse must be greater than or equal to the high voltage of the disconnected circuit. Due to the very low resistance of the fuse, the voltage rating of the fuse becomes important only when the fuse attempts to blow. After the fuse element melts, the fuse must be able to quickly disconnect, extinguish the arc, and prevent the open circuit voltage from triggering the arc again through the disconnected fuse element. 2. Current Ratings: The current rating indicates the current carrying capacity of the fuse under a set of test conditions. Each fuse will indicate the current rating, which can be marked with numbers, letters, or colors. The meaning of each marker can be found through the product data table. 3. Breaking Capacity/Interrupting Rating: The fuse must be able to disconnect the faulty circuit without damaging the surrounding circuit. Breaking capacity refers to the current value at which a fuse can safely open a circuit without da
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Add: Jinyuan Industrial zone,Heao, Henggang, Shenzhen 518115,China
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