Re: Hmm!
- From: "Phil Allison" <philallison@xxxxxxxxxx>
- Date: Mon, 28 Apr 2008 09:25:38 +1000
"Trevor Wilson"
I wonder what the DC resistance of a 250mA fuse might
be?
**Depends on the fuse. I just measured half a dozen 0.25 Amp 3AG fuses.
They ranged from 12 Ohms up to 15 Ohms. COLD.
** That is an unbelievably high resistance value - not at all consistent
with a 250mA fuse.
Some no brand, 1/4 amp 3AG fuses I checked ranged from 3.5 to 4.5 ohms.
These 20mm "T" or delay fuses from Bussman are speced at 0.66 ohms for a
250mA size:
http://www.farnell.com/datasheets/81115.pdf
The specs show that R rises to 1 ohm at rated current.
** Fuses act as non-linear resistors. They get hot and change resistance.
** Speaker voice coils do that too.
...... Phil
.
