through-hole resistors and neodymium magnets

I can't imagine a magnet would harm a resistor. What would make you think it might? Maybe if the magnet were large enough and you dropped it on the resistor pack it could cause damage.

I can't see any reason it would. They don't seem strong enough to cause str uctural damage. The only possible side effect I can see is the resistor its elf or its leads becoming magnetized over time, and being unsuitable for in stallation in near components that are sensitive to magnetic fields.

I just figured it worth brainstorming before I do it to my entire collectio n of resistors and someone tells me "gee that was stupid, didn't you know X would happen and ruin all your resistors?"

On Wed, 1 Oct 2014 22:04:29 -0700 (PDT), snipped-for-privacy@gmail.com Gave us:

It will not affect them in any way. Even if they were "exposed" for hundreds of years.

it might magnetise parts of them them, this shouldn't be a problem for most applications.

If the leads were Kovar, they might get magnetized, but otherwise not.

Cheers

Phil Hobbs

if you're worried, simply 'degauss' them before you use them, else the magnetized lead could do some unknown electrolizing on your PCB causing deterioration?

Radio Shack used to sell a handheld VCR Tape Demagnetizer for around $15.

VCR Tape? Wasn't that something from the last century?

Just kidding, still have at last three in use. My wife is hoarding recorders and video tapes. She keeps checking the Goodwill and Salvation army, she records her soaps and is prepared for the future. In coming months, our cable company will change to (?) a completely digital mode and we will need a box to decode, (at each tv ?). I don't know what she will do then, she's frugal, I don't know if she will find it economically worthwhile to get the DVR. Mikek

On Thu, 02 Oct 2014 10:01:08 -0400, Phil Hobbs Gave us:

Oddly, radial leaded glass body diodes, and radial leaded dipped caps have leads that exhibit rust and magnetic properties. Why the industry ever tolerated that, I'll never know.

Copper is expensive! Lots of cheap parts have tinned steel leads.

That metallurgy is a little off; you don't ever want copper to contact silicon directly, it kills the carrier lifetime. More important, 'tinned' contact springs are the doping scheme for point-contact diodes. The 'tin' is actually the doping metal, perhaps arsenic, and a heat pulse causes it to diffuse around the contact point to form the junction.

I try to keep any tools I'll use on SMT parts Degaussed, so I wouldn't want any purposefully magnetized parts around.

If you build sufficient fun projects, maybe you could use all of the resistors up. Problem solved.

ChesterW

The diodes are easy to understand, because Kovar has the same CTE over temperature as the glasses they used for encapsulation and hermetic sealing. Dunno about the caps--maybe they used Kovar or Copperweld (copper-coated steel) for its mechanical properties. Big dipped caps have a tendency to fall off due to metal fatigue under vibration, and steel is probably better than copper.

Cheers

Phil Hobbs