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Through hole F3 fuse equivalent
Posted: Mon Apr 03, 2017 3:17 pm
by Racer_Rob
I have a Raspberry Pi 1 Model B which I'd like to power through the 5V pins using my own Pi HAT PCB and a regulated 5V supply.
I believe by not using the microUSB the only protection I'm bypassing is the F3 fuse (correct me if I'm wrong).
I want to put a
through hole resettable fuse equivalent to the F3 on my PCB but I'm not clear if 1.1A is the trip current or the hold current?
Re: Through hole F3 fuse equivalent
Posted: Mon Apr 03, 2017 4:42 pm
by drgeoff
Hold.
Re: Through hole F3 fuse equivalent
Posted: Mon Apr 03, 2017 5:07 pm
by Racer_Rob
drgeoff wrote:Hold.
Thanks for the reply. So something like this would be suitable:
RS 647-8522
Re: Through hole F3 fuse equivalent
Posted: Mon May 08, 2017 10:04 am
by Racer_Rob
After some more reading (
here and
here), my understanding is the value printed on the fuse (0.75A) represents the hold current. It trips (i.e. is fully open) at 1.1A.
In which case a through hole equivalent would be more like
712-7480 on RS.
Re: Through hole F3 fuse equivalent
Posted: Mon May 08, 2017 12:10 pm
by klricks
I believe the 1V1 (trip) printed on the schematic is not correct.
The part on the board is marked 750mA (hold).
Typically trip current is 2x hold so that would make 1.5A trip.
I can readily find fuses with those specs but can't find any datasheets with a part that has 750mA hold and 1V1 trip.
IIWM I would probably go with a ~1.0A hold device.....
Re: Through hole F3 fuse equivalent
Posted: Mon May 08, 2017 12:50 pm
by Racer_Rob
Thanks for the clarification, much appreciated
