What are 0 ohm resistors for?

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Ok, so I know I am new at the hardware side of things but this one makes NO sense to me.

A buddy of mine at work insisted that they make 0 ohm resistors. I said "Of course they do. It is called wire and in comes in many sizes and colors." Then he pulls out the digikey catalog and shows me! He didn't know why and I can see why someone would spend almost a dollar on a 50mm length of wire when you can buy a 30m spool of 22 gauge for $15.

http://dkc3.digikey.com/PDF/T073/P1678.pdf

There has to be a reason someone would go the the expense of manufacturing these things. What am I missing?

I don't mind loosing beer bets (as I did on this) but there is NO WAY an entire industry is conspiring against me.

You can have my mac when you pry my cold dead fingers off of it.

Kevin McEnhill -- mcenhillk@gmail.com

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Since 0 Ohm resistors look the same as its resistive brothers, it can be treated the same way in f.i. automatic insertion machines for PCB-manufacturing.

In SMT they are commonly used to let tracks on one side of the PCB cross: the second track goes between the 2 pads of the smd-resistor of 0 Ohm

Third reason is to use them as configuration resistors. (Have a look at the schematic of the Butterfly: you'll find several of these 0 Ohm resistors)

So yes, you'll have to buy him a beer. Cheers !

Nard

Dragon broken ? Or problems with the Parallel Port Programmer ? Scroll down on my projects-page http://www.aplomb.nl/TechStuff/TechStuff.html for tips

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This reminds me on a tube I once saw in a tube-museum.
They had lots of diodes,triodes, tetrodes,pentodes and
so on, but the exhibition also showed a Nullode, a
tube with NULL (=zero) electrodes. I think I was
disturbed the same way you have been about 0-Ohm
resistors.

But there is an explanation. As often, Google knows
the answer also !

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Well, consider that you have a PCB with options. Say you remove or add options. The "Zero Ohm " may be used to enable an input that would otherwise be inhibited, with out the "Zero Ohm " resistor to pull that input to VCC or GND.

In my serial backpack, I use "Zero Ohm " resistors s jumpers to set the BAUD rate to 115.2K BAUD as the default when it is shipped. If the end user wants one of the other three available BAUD rate, one or both of the "Zero Ohm " jumpers are removed. The internal pull up resistors take care of the reset.

It so happens that I primarily make single sided PCBs for most of my projects. "Zero Ohm " resistors are great for use as jumpers, eliminating the need to drill holes and insert "Thru-Hole " jumpers.

Handy devices, they are - "Zero Ohm " resistors...

Also, several months ago, there was a thread where, the exact same question about "Zero Ohm " resistors was asked. You might do a forum search or Google search and see what turns up.

Carl W. Livingston, KC5OTL
microcarl@roadrunner.com

"There are only two ways to sleep well at night... be ignorant or be prepared."

The original Dragon Slayer !

Long live the AVR!!!

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microcarl wrote:
In my serial backpack, I use "Zero Ohm " resistors s jumpers to set the BAUD rate to 115.2K BAUD as the default when it is shipped. If the end user wants one of the other three available BAUD rate, one or both of the "Zero Ohm " jumpers are removed. The internal pull up resistors take care of the reset.
That works very well in your serial backpack. I've been greatly enjoying the serial backpacks I got from you and am preparing to soon post a review of your fine project.

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We use lots of 0 Ohm resistors in our prototype cel phone designs at work. Since things are in the early prototype phase, there's often several possible configurations. Since it's very expensive to set up and run a PCB build, 0 Ohms are often placed around to allow for multiple configurations. Connect something one way and if you want to test the other way, populate a few and remove a few and you have the other configuration.

Don't worry, though, caught me by surprise a bit when I first saw them, too =)

Clancy
_________________
Step 1: RTFM
Step 2: RTFF (Forums)
Step 3: RTFG (Google)
Step 4: Post

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Yeah, it seems to me that they would just be used in cases where it's impracticable or undesirable to solder a jumper wire when you can cross a PCB route with an SMD device (that can be used by an auto-pickup and batch soldered.)

If there's 0-ohm thru-hole versions though, that would not make much sense to me...

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Quote:
If there's 0-ohm thru-hole versions though, that would not make much sense to me...
See my first post in this thread :)

Dragon broken ? Or problems with the Parallel Port Programmer ? Scroll down on my projects-page http://www.aplomb.nl/TechStuff/TechStuff.html for tips

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Yep. :)
And clpalmer beat me to the other thing I was going to say too, so yeah, I got to this thread way too late.

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Psychlow wrote:
If there's 0-ohm thru-hole versions though, that would not make much sense to me...

Then you haven't done much PCB layout using thru-hole components. If making single sided PCBs, thru-hole "Zero Onm " resistors are essential - especially when the PCB is stuffed via "Auto Insertion " equipment.

Carl W. Livingston, KC5OTL
microcarl@roadrunner.com

"There are only two ways to sleep well at night... be ignorant or be prepared."

The original Dragon Slayer !

Long live the AVR!!!

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Incidentally, zero-ohm resistors are anything but. I remembera buddy of mine used one in a pinch to create a low current ammeter. I must say it worked rather well too.

Jim

I would rather attempt something great and fail, than to attempt nothing and succeed. - Fortune cookie

George Orwell wrote about the future, and people called it fiction.

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jgmdesign wrote:
Incidentally, zero-ohm resistors are anything but. I remembera buddy of mine used one in a pinch to create a low current ammeter. I must say it worked rather well too.

Jim

Very true! They can range from a few milli-Ohms to nearly an 1ohm. But they aren't tested for any particular range of values, though...

Carl W. Livingston, KC5OTL
microcarl@roadrunner.com

"There are only two ways to sleep well at night... be ignorant or be prepared."

The original Dragon Slayer !

Long live the AVR!!!

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microcarl wrote:
Then you haven't done much PCB layout using thru-hole components. If making single sided PCBs, thru-hole "Zero Onm " resistors are essential - especially when the PCB is stuffed via "Auto Insertion " equipment.

I've done plenty of single-sided PCBs, but always home made and no auto-insertion equipment.

I'm not understanding something key, I guess - Why can't the equipment just be set up to insert a length of jumper wire?

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See the picture for how resistors get fed into the automatic insertion machine.
It takes one tool for all resistors of a certain wattage and such.
For wire-bridges, a special tool would be required to handle those: so ONE tool for ONE specific component. See the cost-issue ? And extra labour it would take ?
And for that same reason, packages of IC's are standarized.

Nard

Attachment(s): 

Dragon broken ? Or problems with the Parallel Port Programmer ? Scroll down on my projects-page http://www.aplomb.nl/TechStuff/TechStuff.html for tips

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That does make sense. The automatic insertion machines I've seen have been able to insert these though:

Just depends on the machine then, I suppose. :)

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I think you took that from your toy tank. Now, go put it back. :wink:

I would rather attempt something great and fail, than to attempt nothing and succeed. - Fortune cookie

George Orwell wrote about the future, and people called it fiction.

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They also make DED's or Dark Emitting Diodes.

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TMBartman wrote:
They also make DED's or Dark Emitting Diodes.

You mean we could use them to save the universe?

Mankind 'shortening the universe's life' (Telegraph)
http://ars.userfriendly.org/cartoons/?id=20071203

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jgmdesign wrote:
Incidentally, zero-ohm resistors are anything but. I remembera buddy of mine used one in a pinch to create a low current ammeter. I must say it worked rather well too.

Jim


It probably depends on the tolerance. I always pay that little bit extra for 1% 0 Ohm resistors.
[Edit]Although, strangely, they always seem to be over 0 Ohms, I've hardly ever had one that's under...[/Edit]

Act now, think later.

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Mr John A Brown! After a realy shitty day you saved it all with your post! Still laughing!

"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington]

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John_A_Brown wrote:
[Edit]Although, strangely, they always seem to be over 0 Ohms, I've hardly ever had one that's under...[/Edit]

And it'll be a really, really cold day in Hell when a Zero Ohm resistor actually does get all the way down to Zero Ohms!

Carl W. Livingston, KC5OTL
microcarl@roadrunner.com

"There are only two ways to sleep well at night... be ignorant or be prepared."

The original Dragon Slayer !

Long live the AVR!!!

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microcarl wrote:
And it'll be a really, really cold day in Hell when a Zero Ohm resistor actually does get all the way down to Zero Ohms!

Perhaps around –273.15 °C?

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Oh Hell, can we put this to bed already!!! :twisted:

Jim

I would rather attempt something great and fail, than to attempt nothing and succeed. - Fortune cookie

George Orwell wrote about the future, and people called it fiction.

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John_A_Brown wrote:
It probably depends on the tolerance. I always pay that little bit extra for 1% 0 Ohm resistors.

You're being ripped off. 1% of 0R is 0... 5% of 0R is 0....

:lol:

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Geoff wrote:
John_A_Brown wrote:
It probably depends on the tolerance. I always pay that little bit extra for 1% 0 Ohm resistors.

You're being ripped off. 1% of 0R is 0... 5% of 0R is 0....

:lol:


I know - that was the whole point of the post. It was intended to be a joke. :roll:

Act now, think later.

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Sorry old chap, I'm not accustomed to dry wit in a place that doesn't even understand sarcasm.

Well played :)

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I've got one specific board that I use in several products. Some products require an inline 1A diode, other do not. For a while, we were simply using the bare legs trimmed off of other resistors as jumpers, and this worked great.

However, they didn't look all that "professional" and they got to be a pain picking up off of the work bench. We then switched to the 0 ohm resistors. All of our boards are through hole and hand soldered. The overall cost for a 0 ohm resistor is $0.014 per resistor (digikey part 0.0EBK-ND) when bought 1,000 at a time. The appearance of the 0 ohm resistor vs the appearance of a leg or wire is worth the 1.4 cents to me. They, in my experiance, are also a bit easier to work with, because they are indentical to the other resitors we use.

My final advantage is when people open up our products to sneak a peek they are usually confused about what the 0 ohm "resistor" is. That, alone, is worth the penny and a half!

--------------------------------
Kevin Pierson

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John_A_Brown wrote:
Geoff wrote:
John_A_Brown wrote:
It probably depends on the tolerance. I always pay that little bit extra for 1% 0 Ohm resistors.

You're being ripped off. 1% of 0R is 0... 5% of 0R is 0....

:lol:


I know - that was the whole point of the post. It was intended to be a joke. :roll:

Y'all have short memories. As I'm fond of saying, the beauty of this site is that in the storehouse of knowledge on every possible AVR-related (or unrelated) topic the question has already been posed and a consensus answer reached. In the case of zero ohm +/- 1% resistors:
http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=52776&start=all&postdays=0&postorder=asc

Now, note at DigiKey that these zero-ohm resistors come in different wattages. Please help me to understand how to choose between a 1W and 0.1W zero-ohm resistor-- say, 5VDC @100mA and 1000mA. ;)

Lee

You can put lipstick on a pig, but it is still a pig.

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Sorry, Lee, for unwittingly infringing on your copyright.
Just goes to show, there's no such thing as a new joke, or an original thought.

Act now, think later.

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theusch wrote:
Now, note at DigiKey that these zero-ohm resistors come in different wattages. Please help me to understand how to choose between a 1W and 0.1W zero-ohm resistor-- say, 5VDC @100mA and 1000mA. ;)

Use the 1W, it will have a larger body and therefore run cooler!

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Quote:

Use the 1W, it will have a larger body and therefore run cooler!

Dry wit I presume.

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microcarl wrote:
And it'll be a really, really cold day in Hell when a Zero Ohm resistor actually does get all the way down to Zero Ohms!
Phil Bertoni wrote a short story about that day.

Is it racist to discriminate against someone who changes species?

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If the component is to provide zero, then why are we payin so much?

Jim

I would rather attempt something great and fail, than to attempt nothing and succeed. - Fortune cookie

George Orwell wrote about the future, and people called it fiction.

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Sony used to use zero ohm resistors as overload devices (much like fuses). They probably still do.

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The_village_idiot wrote:
Sony used to use zero ohm resistors as overload devices (much like fuses). They probably still do.

Ah! But you forgot to mention that the Zero Ohm resistors that are used as overload devices are actually calibrated to fail at a specific current, making them precision speciality Zero Ohm devices...

The plot thickens!!!

theusch wrote:
Please help me to understand how to choose between a 1W and 0.1W zero-ohm resistor-- say, 5VDC @100mA and 1000mA.

So, if the Zero Ohm resistor really exhibits some finite resistance, say, 0.025 Ohms...

P = I2R

If there is, say, 10mA of current flowing through that Zero Ohm resistor, then:

P = 0.01 * 0.01 * 0.025 = 0.0000025 Watts or, 2.5uW

That's pretty damn small!

You can just scale up the current values.

And you can bet that the resistor manufacturer will specify some nominal resistance for each wattage of Zero Ohm resistor in the data-sheet.

Data-sheet??? Uh???

The attached is from:
http://www.koaspeer.com/resistors.asp?part=16

And from WikipediA:
http://en.wikipedia.org/wiki/Zero-ohm_link

Quote:
Zero-ohm link
From Wikipedia, the free encyclopedia
Jump to: navigation, search
A zero-ohm link or zero-ohm resistor is a wire link used to connect traces on a printed circuit board that is packaged in the same format as a resistor. This format allows it to be placed on the circuit board using same automated equipment used to place other resistors instead of requiring a separate machine to install a jumper or other wire. Zero-ohm resistors may be packaged like cylindrical resistors, or like surface-mount resistors.

"000" and "0000" sometimes appear as values on surface-mount zero-ohm links, since these have (approximately) zero resistance. Alternatively, a single black line may be used to denote zero ohms using the resistor color code on a cylindrical zero-ohm resistor.

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Carl W. Livingston, KC5OTL
microcarl@roadrunner.com

"There are only two ways to sleep well at night... be ignorant or be prepared."

The original Dragon Slayer !

Long live the AVR!!!

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Often precision specialty smokeless devices. Which means that they either have no magic, or it is so well contained that the secret magic smoke is never allowed to escape.

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Zero-ohm resistors are pretty much used as jumper wires on pcbs. They are used because the machines which put together pcb circuits handle components much more better than jumper wires. In fact, these machines don't even deal with jumper wires. So zero-ohm resistors are used instead.

LINK REMOVED

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Don't you feel the least bit odd answering to a 5 year old post? :roll: Welcome to the forum. :)

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That, or crappy attempt to market a website for some reason.

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I've heard that zero ohm resistors are used used in the control electronics of superconducting magnets. YukYukYuk.

Imagecraft compiler user

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I heard they are used to minimise power loss ... I^2R

Ross McKenzie ValuSoft Melbourne Australia

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mcenhillk wrote:
I can see why someone would spend almost a dollar on a 50mm length of wire when you can buy a 30m spool of 22 gauge for $15.

A dollar!? They should be available at the same price as regular resistors!

I have them available as leaded components from roughly 5 cents a piece (if I buy 50), didn't check surface mount prices! :)

- Brian

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At the time I posted, no! ;) Also I did not see the age of the original post!
I did see it immediately afterwards however, but I didn't want to change my post...

That's what you get for thread necromancy! Whoever revived this thread! :roll:

- Brian

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Quote:

Whoever revived this thread!

A spammer - you've been indirectly trolled.