Resistor/Fuse replacement (DEC H7104-D)
v.slyngstad at frontier.com
Tue Mar 22 10:20:27 CDT 2016
From: drlegendre: Monday, March 21, 2016 6:50 PM
> I don't quite get what makes this DigiKey part suitable for the role of a
> fused resistor. I do see that it has specs for 'fusing behavior' but that
> aside, I don't see that this series is marketed / sold as a "fusible
I take "UL1412 recognised fusing" (sic) on the first line of the data sheet
to mean that they do market them that way.
> One reason I question it, is the fact that the fusing ratings are only
> plotted for like 40X or 50X expected current. Can the circuit under
> protection be relied upon to produce those levels of current, even under
> hard-fault conditions?
I read a little over 1000 seconds to fuse at 10W, which is only a
few times the 2W rating. Admittedly, 20 minutes at 5X load
amounts to a pretty slow fuse. I can only assume their concern
is fire prevention, rather than circuitry protection.
With regard to the suggestion of a fuse and a resistor, you'd
need more room (likely not a problem), and a flameproof
version of the resistor. I don't know anything about UL
ratings, so I don't know if that could be made OK there or
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