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Old 23rd August 2005, 05:27 AM   #21
zanash is offline zanash  United Kingdom
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should have added from the same maker ! The better sounding resistors tend to be those with better specs wether they are carbon or metal film construction.
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Old 16th June 2010, 03:53 AM   #22
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Quote:
Originally Posted by SY View Post
I don't want to be the skunk at the picnic, but...

Nichrome is not ferromagnetic.

If it were, the film is too thin to have any significant attraction to a magnet.

What the magnet is attracting is the ferromagnetic end caps which make contact with the resistive film/ceramic substrate.
Ran across this thread earlier today.

I find both NiCr Susumu thin film ($0.40) and Vishay bulk metal foil ($20) SMT resistors are weakly attracted and stick to rare earth magnets. If I can find ones that I don't need, I'll cut the ends off to isolate where the attraction is.
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Old 16th June 2010, 04:42 AM   #23
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TaN film SMT also attracted to rare earth. And $20.40 later, find that it is indeed as Sy indicated--the ends of the Susumu/Vishay are attracted.

Of TH resistors, "superb PRP 9372 audio grade metal films from Precision Resistive Products" very attracted even the body. Of the resistors I tested, only Holco resistors are standoff-ish.

(Least now I know which resistor will make my audio arc welder sound best :P . . . jk)
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Old 16th June 2010, 09:01 AM   #24
mt490 is offline mt490  Australia
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Quote:
Originally Posted by peranders View Post
.... so what exacltly does the magnetism do? Nobody have to answer because this is only a fashion, no?
It's used in some automated assembly processes.

Quite a few components have magnetic leads as well, not just the body. Capacitors, glass body diodes and resistors.
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Old 16th June 2010, 02:02 PM   #25
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Originally Posted by mt490 View Post
It's used in some automated assembly processes.

Quite a few components have magnetic leads as well, not just the body. Capacitors, glass body diodes and resistors.
Pick and place . . . that explains it. Cool ! ! !
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Old 16th June 2010, 03:11 PM   #26
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I've never seen magnetism used by pick and place.
Steel/iron is much cheaper than copper
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Old 17th June 2010, 11:40 AM   #27
marce is offline marce  United Kingdom
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Pick and place use vacuum, never magnetism, just to second Davids comment.
As these components are going to be in circuits with ac, how is the megnetism gonna effect ANYTHING! Just curious.
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Old 17th June 2010, 03:10 PM   #28
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Long ago I was developing broadcast tv monitors. We had a horrible kink in the display that was eventually traced to a TI 741 in the psu with a ferrous lead frame picking up the field from the scan coil. Changing to another vendor solved the problem.

Iron leads can make good low frequency antennas
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Old 17th June 2010, 05:01 PM   #29
marce is offline marce  United Kingdom
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Yes in a colour monitor with HT, line transformer maybe, but these days with our awareness of emc etc, I have never known an engineer these days to be concerned with some slight magnetism in components, apart from transformers and inductors, and when designing a PCB or an assembly you keep sensitive circuitry away from such things.
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Old 19th June 2010, 06:29 AM   #30
marce is offline marce  United Kingdom
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Davidsrsb, was around the time when TI came up with the EMC coating for thier chips to help combat what was a major EMC faux pas.
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