Re: [Phys-L] ceramic fuses

[Chuck Britton <cvbritton@mac.com>]

I respectfully disagree.
It is my opinion that the CONTACT resistance at the ends of the fuse will be comparable to the resistance of the 1/4 amp fuse itself.
Your discussions (or lack thereof) with the meter vendor reinforces my position (Again - in my humble opinion.)

If the meter manufacturer is in fact using the fuse element as a critical component in the measuring circuit - I'd like to hear about it and recommend another brand of meter.

I'd buy the cheapest 1/4 amp fuse you can acquire. 
If the form-factor is right and the voltage spec matches - you're good to go.

Another consideration is slow-blow vs standard vs FAST.  (FAST is used to protect delicate expensive stuff - not student meters)

Cheers

On Aug 20, 2012, at 11:03 AM, George M Caplan wrote:

> I would use exactly the fuse specified.
> In addition to safety reasons, here's another reason:
> The resistance of the fuse determines (in part) the resistance of the ammeter.
> If the resistance changes with current as the fuse heats up, the
> resistance of the ammeter will not be constant.
> This problem exists even when using the proper fuse in at least one
> model of Extech multimeter.
> I spoke to a very nice fellow at Extech about this. He said he'd check
> with engineers.
> After I spoke to him twice, he stopped returning my calls.!