Out-of-tolerance zero ohm resistors

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An assembly house apparently substituted some 1210 zero-ohm resistors with
another mfr's part.  They're passing >10A, so part characteristics matter.

The substitute parts measure 12.5 milliohms, dissipating an extra 1.3W
in an enclosed unit that doesn't appreciate that.

The Vishay parts spec'd list 4 milliohms max, but actually measure 2.5
milliohms.  Much better.

Just for fun I measured the drop across the solder fillets too--only 1mV
out of 126mV total.  Insignificant.

I figure they're both out of tolerance though, one by infinity percent, and
the other by 5*infinity percent.

Someone put those in for <I don't know what>. We'll replace 'em with a
copper trace next time.  Meanwhile, Keystone has some *really* good
alternatives, 0.2 milliohms max.

http://keyelco.com/product.cfm/Zero-ohm-SMT-Jumpers/1206-Zero-ohm-SMT-Jumper/product_id/14040

That's still .2/2.5 * infinity percent over spec though.

Cheers,
James Arthur

Re: Out-of-tolerance zero ohm resistors
On a sunny day (Fri, 29 May 2015 08:13:23 -0700 (PDT)) it happened
snipped-for-privacy@yahoo.com wrote in

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Try to but some with negative R.

Re: Out-of-tolerance zero ohm resistors
On Fri, 29 May 2015 15:58:58 GMT, Jan Panteltje

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They would have to be shipped with "keepers", like some supermagnets
or big energy storage caps. UPS probably wouldn't allow them.


--  

John Larkin         Highland Technology, Inc
picosecond timing   laser drivers and controllers

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Re: Out-of-tolerance zero ohm resistors
On Friday, May 29, 2015 at 12:12:18 PM UTC-4, John Larkin wrote:
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Marketing slogan: "Resistance is futile."

Cheers,
James Arthur

Re: Out-of-tolerance zero ohm resistors
On Fri, 29 May 2015 09:21:22 -0700 (PDT), snipped-for-privacy@yahoo.com
wrote:

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You have nothing to lose but your ohms.


--  

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement  

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Re: Out-of-tolerance zero ohm resistors
On Fri, 29 May 2015 09:50:50 -0700, John Larkin

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  "All electrons will be assimilated..."

Re: Out-of-tolerance zero ohm resistors
On Fri, 29 May 2015 09:21:22 -0700 (PDT), snipped-for-privacy@yahoo.com Gave
us:

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You have to say that like Yoda in this instance....

  "Futile, resistance is..."

Re: Out-of-tolerance zero ohm resistors
On a sunny day (Sat, 30 May 2015 17:30:49 +1000) it happened Clifford Heath

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Use Opamps :-)

Re: Out-of-tolerance zero ohm resistors
On 5/29/2015 11:13 AM, snipped-for-privacy@yahoo.com wrote:
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I seem to recall seeing a zero ohm resistor having the same tolerance  
spec as the other parts in the family, 1%.  That's a tough standard for  
zero resistance.

--  

Rick

Re: Out-of-tolerance zero ohm resistors
On 2015-05-29 9:33 AM, rickman wrote:
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I want the ones that are -1%.

--  
Regards, Joerg

http://www.analogconsultants.com/

Re: Out-of-tolerance zero ohm resistors
On Saturday, May 30, 2015 at 3:27:05 PM UTC-4, Joerg wrote:
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Hmm, If you make an active negative resistance,
does it have Johnson noise?

George H.

Re: Out-of-tolerance zero ohm resistors
On Sun, 31 May 2015 17:20:09 -0700 (PDT), George Herold

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  Depends on whether or not he got schott along the way.

  Don't poisson yourself trying to figure it out.

  Iz it twoo what they say?

  The Johnson noise only shows up when you are in Rock Ridge.

  Mongo likes beans.  1 over f...    FART!  noise!

Re: Out-of-tolerance zero ohm resistors
On Sun, 31 May 2015 17:20:09 -0700 (PDT), George Herold

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Sure.


--  

John Larkin         Highland Technology, Inc
picosecond timing   laser drivers and controllers

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Re: Out-of-tolerance zero ohm resistors
On 06/01/2015 11:53 AM, John Larkin wrote:
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Purely imaginary, of course. ;)

Cheers

Phil Hobbs


--  
Dr Philip C D Hobbs
Principal Consultant
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Re: Out-of-tolerance zero ohm resistors
On Mon, 01 Jun 2015 14:34:36 -0400, Phil Hobbs

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  Unless you are in Rock Ridge.  There is a huge amount of Johnson noise
there, regardless of the resistance value.  :-)

http://www.imdb.com/title/tt0071230/


Re: Out-of-tolerance zero ohm resistors
Am 01.06.2015 um 17:53 schrieb John Larkin:
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.. and if you have 50 Ohms and -50 Ohms in series,
I'd bet that not many simulators get the noise right
thanks to node collapsing?

regards, Gerhard





Re: Out-of-tolerance zero ohm resistors
On 2015-06-01 12:38 PM, Gerhard Hoffmann wrote:
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According to politicians and federal bankers there would be no node  
collapse as this would still total about +32 ohms. Or over +60ohms in  
Greece :-)

--  
Regards, Joerg

http://www.analogconsultants.com/

Re: Out-of-tolerance zero ohm resistors
wrote:

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Well, they did invent the omega.


--  

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement  

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Re: Out-of-tolerance zero ohm resistors
On Mon, 01 Jun 2015 17:05:17 -0700, John Larkin

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snip

  No...  that was Zeus.

Re: Out-of-tolerance zero ohm resistors
wrote:

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Isn't that the tax on your ohms?

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