From: Harold Hallikainen <harold@mai.hallikainen.org>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Thu, 12 Aug 2021 16:18:28 -0700
Subject: Re: [EE] PTC fuse voltage
Thread-Topic: [EE] PTC fuse voltage
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> What exactly is the voltage rating of a PTC fuse?=C2=A0 ( I was selecting=
 one
> today and it dawned on me that I never really paid attention to this. )
> As I see it, it has to be the voltage across the fuse, and that's based
> on it's internal resistance the current through it.
> At no point can I see a higher voltage getting across the fuse, so if I
> use it in a circuit that runs at a higher voltage (say a basic PS, fan,
> switch), that should be fine, correct?
>
> Cheers,
> -Neil.

The voltage rating is a concern once the PTC "trips". If it is exceeded,
"bad things" can happen. Several years ago, I also discovered that PTC
overcurrent limiters do not like to be in the tripped state for long
periods of time (like a month or more). I had two instances of them
bursting into flames.

Harold


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