If he's talking about "100 carbon resistors cost 1.41 euro", he's not
talking about carbon composition, but carbon film.
And at the prices he's talking about the resistors probably are rated
for no more than 500V, I'm guessing he's talking about 1/2W or 1/4W
units or less.
In my experience I would rate typical metal films as far better at
handling massive overloads than carbon films. Of course there are
fundamentally different types of metal films (some are high-precision,
others have safety ratings, some might even have both but not at the
price he's talking about!)
Tim.
I hadn't thought of that.. carbon film.. I'd never use them at all, unless
someone can tell me a reason to. I thought they were purely a cost saving
thing where poor tolerances didn't matter, made redundant for most uses
once metal film became cheap.
I still rate the solid carbon ones though, they don't cost that much. I
made a HeNe laser current limit resistor out of 4 2W solid carbons in
adhesive lined heatskrink tubing, and they work well. First tests were with
metal film resistors, but they burned out spectacularly like they might if
I'd microwaved them for fun. I bet carbon film types would be even worse.
I use standard 1% 0.6W metal film types for nearly everything I do, I think
there's no point in trying to save money by using anything less, except
maybe if you're into huge volume production. The difference on cost is far
less than the worth of time lost in solving problems with bad resistors.