Selection of resettable fuse

qwqwqw2088

Selection of resettable fuse [Copy link]

The following issues should be considered when selecting a resettable fuse: 1) In the circuit, what is the voltage value across the series pptc element? 2) When the circuit is in normal operation, what is the average current value flowing through the pptc element? 3) When the circuit is short-circuited, how much fault current in the circuit will cause damage to the circuit or other components in the circuit? Maximum limiting current, such as: when the circuit is protected, when the circuit load and the fault current increases to 10 amperes, the circuit or the components in the circuit will be damaged, affecting the normal operation of the circuit, and the pptc element is needed to quickly protect the circuit. The current value at this time is the limiting current value. 4) What is the ambient temperature of the circuit? (Because the pptc element is a positive temperature coefficient thermistor, it is affected by the ambient temperature) 5) How long does the circuit work? (Is the circuit working continuously for a long time (more than 4 hours) or intermittently) Parameters of resettable fuse Holding current (IH): The highest current that does not trigger a resistance jump in a 25℃ still air environment. Triggering current (IT): The minimum current at which the PTC polymer resettable fuse changes from low resistance to high impedance in a 25℃ still air environment. Maximum voltage (VMAX): The maximum working voltage of the PTC polymer resettable fuse. Maximum current (IMAX): The maximum current that the PTC polymer resettable fuse can withstand. Action power (PDTYP.): The power consumption of the PTC polymer resettable fuse in the action state at an ambient temperature of 25℃. Action time (TTRIP): The maximum action time at 5 times the holding current. Tmax: Maximum overload current operating time Rmin: Minimum resistance (25℃) Rmax: Maximum resistance (25℃)