This is a homebrew self-repairing 5A fuse which uses a PPTC or PolyFuse. I've also added an indicator lamp which shows when the fuse has blown.
The fuse doesn't actually blow; it just flips from a low resistance to a high resistance when its temperature reaches a certain point.By removing the high current path, the fuse cools down and its low resistance is restored.

By Julian

Youtuber, shed dweller, solar charge controller aficionado

12 thoughts on “5a pptc polyfuse repairs itself automatically after it blows”
  1. Avataaar/Circle Created with python_avatars Departement Sciences says:

    cool video! However, is it possible it would take way longer time to blow if I use a small polyswitch (let say 100mA trip current) would be used? I bought some small polyswitch to use them on breadboard to protect ampmeter: students have bad tendency to mount ampmeter in parallel and blow fuse in multimeter! I was expecting polyswitch to blow few sec after trip current reached but nope! Any idea or hints to protect multimeter?

  2. Avataaar/Circle Created with python_avatars MULONDA MWINANU says:

    I used 230v AC, 3A PPTC and it works perfectly in times of electric short circuits.

  3. Avataaar/Circle Created with python_avatars David Kaštánek says:

    Fixed my car battery charger thanks to this info. Thank you 🙂

  4. Avataaar/Circle Created with python_avatars Hamed Adefuwa says:

    Just ordered one now, Ty ❤️

  5. Avataaar/Circle Created with python_avatars Lee Kyo says:

    NEW TECHNOLOGY OF REUSEABLE FUSE IS GREAT

  6. Avataaar/Circle Created with python_avatars INNOVATION & INITIATIVE Diy says:

    Very nice demonstration

  7. Avataaar/Circle Created with python_avatars phil says:

    this is what i am looking for! thanks!

  8. Avataaar/Circle Created with python_avatars TheOpenSource says:

    "Cleva girl…" I love the simplicity of application to complexity of provided solution.

  9. Avataaar/Circle Created with python_avatars Guds777 says:

    So it is a bimetal fuse…

  10. Avataaar/Circle Created with python_avatars electronige says:

    19 seconds ! still do v helpful vid to see them in action

  11. Avataaar/Circle Created with python_avatars Zaha Hana says:

    thanks ,,, but why the lamp not coming ON during the current flow even before the fuse becoming hot since the lamp connected with the fuse in parallel

  12. Avataaar/Circle Created with python_avatars Brett says:

    Does it get hot at any point?

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