joseph20480 Posted November 3, 2022 Report Share Posted November 3, 2022 Dear community, I'm playing with PTC resettable fuses and i have some trouble. In effect, i'm not able to retrieve datasheet caracteristics in real life. My PTC reference : Bourns MF-USML/X Series - MF-USML300/6 Vmax : 6v / Ihold :3.0A / Itrip : 6.0A My test : My fuses in serial with 1.7r resistor. Voltage supply 5.1v >>> Current load about 2.7A. My result Each time, after 20-30 sec the fuse break. Second thing, if i try to use it again, the sensibility have been change and break after 2-3sec (same load). My question... Where is my error tell me more is you have an idea. Quote Link to comment Share on other sites More sharing options...
HarryA Posted November 3, 2022 Report Share Posted November 3, 2022 Time plays a big factor with PTCs; 26. Recovery time: The recovery time after PTC thermistor action should not exceed 60S. see: https://www.ntcsensors.com/Technical_parameters_of_PTC_resettable_fuse/#:~:text=Under limited conditions%2C the highest voltage that the,may be broken down and cannot be recovered. Also there is an interesting video that discusses PTCs here: https://www.youtube.com/watch?v=eeaqyD3ZYjI Quote Link to comment Share on other sites More sharing options...
joseph20480 Posted November 3, 2022 Author Report Share Posted November 3, 2022 Sure... but... We are agree to say, like me, that my fuse with an Ihold: 3.0A shouln't break at 2.7A ? I will try to contact Bourns for explication. Understand the phenomena. Quote Link to comment Share on other sites More sharing options...
HarryA Posted November 3, 2022 Report Share Posted November 3, 2022 Sorry they are beyond me. Why would one use a 3 amp fuse that trips at 6 amps? What does the 15 and 50 amps got to do with it? How would it allow current that high? Beware there are a lot of fake components out there. I got some ICs via Amazon.com lately they had the TI symbol on them but also "made in China" on them; never seen TI chips with that on them before. For other viewers: Quote Link to comment Share on other sites More sharing options...
Olivia Duke Posted November 15, 2022 Report Share Posted November 15, 2022 Time plays a big factor with PTCs; 26. Recovery time: The recovery time after PTC thermistor action should not exceed 60S. see: https://www.ntcsensors.com/Technical_parameters_of_PTC_resettable_fuse/#:~:text=Under limited conditions%2C the highest voltage that the,may be broken down and cannot be recovered. Also there is an interesting video that discusses PTCs here: https://www.youtube.com/watch?v=eeaqyD3ZYjI/geometry dash Thank you for sharing! Quote Link to comment Share on other sites More sharing options...
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