metal film or carbon film? - Page 3

zanash · 23rd August 2005, 06:27 AM

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.

johnferrier · 16th June 2010, 04:53 AM

Quote:

Originally Posted by SY

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.

johnferrier · 16th June 2010, 05:42 AM

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)

mt490 · 16th June 2010, 10:01 AM

Quote:

Originally Posted by peranders

.... 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.

johnferrier · 16th June 2010, 03:02 PM

Quote:

Originally Posted by mt490

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 ! ! !

davidsrsb · 16th June 2010, 04:11 PM

I've never seen magnetism used by pick and place.
Steel/iron is much cheaper than copper

marce · 17th June 2010, 12:40 PM

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.

davidsrsb · 17th June 2010, 04:10 PM

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

marce · 17th June 2010, 06:01 PM

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.

marce · 19th June 2010, 07:29 AM

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.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
metal film resistors or carbon?	leitmo	Tubes / Valves	2	28th June 2008 11:14 AM
riken resistors: carbon comp or carbon film?	jarthel	Parts	0	20th October 2006 02:00 AM
Res Survey:....... Carbon film ...or... Metal Film ...............??	nina	Chip Amps	13	14th April 2005 01:46 AM
Carbon film vs metal film resistors in a stepped attenuator?	G	Tubes / Valves	17	22nd August 2004 01:22 AM
Metal film resistors or carbon film in a tube amp?	G	Tubes / Valves	220	31st March 2003 02:57 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

23rd August 2005, 06:27 AM	#21
zanash diyAudio Member Join Date: Feb 2005 Location: Notts	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.

16th June 2010, 05:42 AM	#23
johnferrier diyAudio Member Join Date: Sep 2003 Location: WA	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)

16th June 2010, 04:11 PM	#26
davidsrsb diyAudio Member Join Date: Dec 2005 Location: Kuala Lumpur	I've never seen magnetism used by pick and place. Steel/iron is much cheaper than copper

17th June 2010, 12:40 PM	#27
marce diyAudio Member Join Date: Jun 2007 Location: Blackburn, Lancs	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.

17th June 2010, 04:10 PM	#28
davidsrsb diyAudio Member Join Date: Dec 2005 Location: Kuala Lumpur	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

17th June 2010, 06:01 PM	#29
marce diyAudio Member Join Date: Jun 2007 Location: Blackburn, Lancs	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.

19th June 2010, 07:29 AM	#30
marce diyAudio Member Join Date: Jun 2007 Location: Blackburn, Lancs	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.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)