0 ohm resistor???

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psycho
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0 ohm resistor???

Post by psycho » Thu Feb 28, 2008 12:59 am

I was nosin' around the net for parts deals and stumbled on a resistor assortment :

http://www.opamp-electronics.com/catalo ... p-758.html

They have a 0 ohm resistor. Wouldn't this be a... wire? What would you possibly use this for? Or, is this a typo?

Kevin

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jwax
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Post by jwax » Thu Feb 28, 2008 3:14 am

In manufacturing, it may be a jumper to cross a conductor trace, or it may be there to replace an earlier version that required some resistance.
Yup, it's a "wire".

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dacflyer
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Post by dacflyer » Thu Feb 28, 2008 3:41 am

i deal with lots of "0" ohm resistors, they are basically jumpers
the ones i use. have a tan body with just 1 black band.
i crushed one before, and they are just wire inside, so its just a jumper in a resistor caseing.

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Dave Dixon
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Post by Dave Dixon » Thu Feb 28, 2008 6:17 am

I remember the first time I ran across these... I thought it seemed like an oxymoron! A couple of uses for these. Ever have just ONE trace that you can't seem to route? Jumper over a trace with a "zero ohm resistor". We also use these for a multiple purpose PCB. Install a "jumper" here or there - for example to a microcontroller - and you have a permanent method of giving the PCB the desired "personality". Just like using dip switches or those manual jumpers, but takes up a lot less space, as well as being permanent. I hope I explained these uses well... It's first thing in the morning. Hope this helps,
Dave

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Post by Engineer1138 » Thu Feb 28, 2008 8:12 am

Zero ohm resistors are jumpers, but they are made so they can be handled by automated pick&place machines.

psycho
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Post by psycho » Thu Feb 28, 2008 9:43 am

I figured there had to be a reason, as in pick & place machines, but, kinda a ripoff, including it in an assortment!

Kevin

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Bob Scott
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Post by Bob Scott » Thu Feb 28, 2008 10:11 am

Engineer1138 wrote:Zero ohm resistors are jumpers, but they are made so they can be handled by automated pick&place machines.
Yes, I've seen 0 Ohm resistors used in consumer equipment 25 years ago. I guess shorting wires don't come on tape or reel for the insertion machines.

These 0 Ohm resistors are also useful for CAD schematics. Some (All?) AD and DA converter ICs require that the digital ground and analog ground planes be connected together at the AD IC. CAD programmes (like Orcad) will choke when you short 2 nets with different names together, so you have to install the 0 Ohm resistor as a kluge.

Bob :cool:

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Post by jimandy » Thu Feb 28, 2008 5:02 pm

One must be careful not to confuse it with a zero impedance inductor.
"if it's not another it's one thing."

Dean Huster
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Post by Dean Huster » Thu Feb 28, 2008 7:54 pm

Al;though the automated insertion equipment could be modified to handle plain-wire jumpers, they're usually ready to go for the 1/4-watt resistor package, so it's cheaper to do it that way.

The devices are also good for simulating shorted capactors, however the zero impedance inductors would depend upon the frequency. At a possible 1 nH, I believe you would have around 62 ohms of inductive reactance at 10 GHz.

Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

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Post by cpufixer » Mon Mar 10, 2008 3:50 pm

I used to use them a lot when I was a Field Service technician, many moons ago. On the old computers we used them to configure jumper settings on system boards, old Digital (aka DEC) PDP-08 and PDP-11 systems. They were the ones that had the brown casing and single black stripe, always had a bunch in the tool bag.

The funny part about your link was they have a 5% tolerance :grin:

psycho
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Post by psycho » Tue Mar 11, 2008 2:07 am

The tol is funny, too. But, what posessed them to put them in an asst kit??? Do any of the community members USE them?? Not, "yep... got a few in my junk box". But, rather, "Yeah, I have used them in a hobby type project".

Kevin

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Dave Dixon
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Post by Dave Dixon » Tue Mar 11, 2008 7:02 am

I have used one in a hobby project. I wanted to keep a simple board single sided, and had one stupid trace that I couldn't route for the life of me! I felt like I was cheating, but using it as a jumper over a trace on my board saved either several hours of re-routing, or going to a double sided PCB.

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dacflyer
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Post by dacflyer » Tue Mar 11, 2008 9:14 am

another note, we use them on many programmable boards, its sort of like a hardwire switch, this is to prevent any accidental switches being flipped.
sure a DIP switch would be easier and a lot faster to use,,but the 0 ohm resistors are a failsafe.

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Janitor Tzap
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Post by Janitor Tzap » Tue Mar 11, 2008 1:46 pm

Yup,
seen a lot of 0 ohm resistors used in VCR's, Tuner Packs, Power Supplies.

In the power supply circuit they would act as a fuse.
In many CamCorders it is used for a fuse.

You could just replace it with a wire.
But, in one case I remember that when I did that.
The Camcorder came back with a burned out Capstan Motor Drive IC.
That the 0 ohm resistor was designed to blow if the Capstan Motor starts to draw more current than the normal .5 amp.
Ended up that the bearings on the Capstan Motor were worn out, causing the 0 ohm resistor to blow.

After some checking with suppliers.
I found that I couldn't just replace the Capstan Motor Bears, and the blown Drive IC.
I had to buy a complete Capstan Motor Assembly for the Camcorder.
Which was going cost over $100.00 plus my time and labor.

So, that CamCorder ended up in the junk pile.


Signed: Janitor Tzap

Robert Reed
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Post by Robert Reed » Tue Mar 11, 2008 4:04 pm

"I have used one in a hobby project. I wanted to keep a simple board single sided, and had one stupid trace that I couldn't route for the life of me! I felt like I was cheating, but using it as a jumper over a trace on my board saved either several hours of re-routing, or going to a double sided PCB."

Dave, it also makes it look like just another component and not an "OOPS". The end result is the board still looks highly professional! :grin:

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