PolyFuse for Short Circuit

[walterdsouzajr]

I need a fuse to work when there is a short circuit. Do the
polyfuses do this?

I am doing a DIY project. I really need to know which
polyfuse to buy. I am running between 2volts and 12volts. I
need the connection to be broken when there is a short
circuit and then automatically reset.. The DIY project is comparable to a 9-led flashlight. and I want to wire the polyfuse in the device and not to the
batteries them selfs. If it makes any difference.

If there is another type of fuse I can use please let me know.

 

[Mick]

A polyfuse will have more resistance than a regular fuse and when it blows, then resets, the resistance gets much higher. If you are running a high current this will cause some heating and probably further degrading of the conductivity. I found a mini automotive blade fuse and holder at DigiKey for my battery packs but of course it is a one shot affair.

 

[walterdsouzajr]

The resistance makes such a difference with these fuses? You think I can have a issue with this resistance .

 

[Mick]

I just wanted you to realize that the resistance of a polyfuse increases when it resets. Weather or not it will be a problem depends on the current your light draws. If it is 5 amps and the fuse resistance gets to 50 mOhm then the fuse will dissipate 1.25 watts and is sure to get hot. Lower current levels should not be a problem except for the power wasted by the fuse resistance.