Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [polyfuse]

Questions regarding Polymeric Positive Temperature Coefficient devices, typically known as Polyfuses, PPTC, or Resettable Fuse. They are non-self-destructing versions of Fuses, similar to Circuit Breakers, in that they self reset when the high current draw is removed. Questions about regular fuses should use the Fuse tag.

Questions regarding Polymeric Positive Temperature Coefficient devices, typically known as Polyfuses, PPTC, or Resettable Fuse. They are non-self-destructing versions of Fuses, similar to Circuit Breakers, in that they self reset when the high current draw is removed.

Ployfuses have different applications, and design issues, from fusible links.

Questions about regular fuses (fusible links) should use the tag.

Please keep in mind that repair questions are typically closed if not within the scope of the Site and FAQ.

78 questions
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PTC fuse resistance characteristic?

I'm currently working on a project where I have to take into account the resistance of the in series PTC fuse, however after reading the datasheet I found two specs for resistance Rmin and R1max. I did a little more research and I came across this…
Kvegaoro
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Why are polyfuses so big?

Why are polyfuses so big? I was looking at a 500mA polyfuse, it is in an 0805 package, but there was only one of them - the rest were 1206. I have two questions. Why so big? Does anyone make 0603 polyfuses?
Thomas O
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PTCs on AC/mains line

Why is it that surface mount (SMT) PTC fuses can only be used on DC lines but through-hole PTC fuses can be used for both AC and DC? This came from a cautionary note on one of Bel Fuse's PTC application note documents. Page 3: I've also seen…
YNGVV
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How to use a Polyswitch Self Resetting Fuse and light up led when fuse has been disconnected

I'm designing a circuit that will be connected to usb of a pc. How can I isolate the supply when a short has been detected on any part of the circuit. An led should light up indicating there's a short somewhere in the circuit.
Ageis
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Polyfuse voltage significance

I would like to protect a circuit from overcurrent over 500 mA. The voltage in the circuit is only 5 V. Can I use higher voltage and lower current polyfuse, which results in same power flowing through the polyfuse? Thinking in general, and looking…
zmechanic
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Extending a PTC voltage rating with series resistance

PTCs come with a maximum voltage rating which, according to the answer for this question is essentially because of instantaneous power across the device. Usually, a PTC is placed across a low-resistance voltage source. However, in my case, the PTC…
Damien
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Features of Resettable Fuses

I want to use a resettable fuse for overcurrent protection. I am a bit confused about their features. The hold current is the maximum current for not tripping and the trip current is the mimimum current for tripping, right? Then, what is the current…
Konstantinos Tsoumanis
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Straightening the pins of a resettable polyfuse

I have resettable polyfuses like the picture below. I am working on some PCB boards where I solder the wires myself on the PCB. Because it is very hard/cumbersome work to solder very small wires, I use the leads of components to make a path to a…
Michel Keijzers
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How can PTC resettable fuses (battery strap type) be mounted on PCB?

I need to use a resettable fuse in my design and I'm using something like this: Can strap type fuses be used on PCB and how can they be mounted on PCB?
user39712
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