zero ohm resistors

[peterthenovice]

what is the main application for 0 ohm resistors. I believe is it mainly for pick and place machines. Is it for critical applications? do they have less resistance than
jumper leads?

[ZeroStatic]

Zero ohm resistors are most often just jumpers on the board to jump over a track or two.
Sometimes they are used like switches to set options at maufacture, I've even seen them used not wired to anything to indicate a version by placing them next to various ovelay labels.

On occasion then are used when a resistor was designed into the circuit and was found not to be needed.

Brenden

[alm]

Jumper leads work just fine as long as you have no traces running underneath or the soldermask provides sufficient insulation. Through-hole zero ohm resistors are indeed mainly useful for pick-and-place machines. SMD zero ohm resistors are slightly more useful, since it can be annoying to position a piece of wire or solder blob on the two pads.

[mariush]

Nice and easy way to jump across a few traces, especially if you want to save a few cents on pcb cost by sticking to a single layer pc design.

With really cheap (through hole only for example) FR2 / phenolic /  paper based boards it's even better than plain wires, since lead forming machines for resistors are relatively cheap and you can get a band of 0 ohm resistors through the machine and have the machine bend the leads to a particular size and cut the excess wire in one go.

[robrenz]

Some zero ohm resistors specs can be as high as 20 mOhms.  Usualy would not cause a problem but be aware.

[AlfBaz]

In some circuits its very difficult to tell wether you are going to need a resistance in place until the PCB is built. Crystal oscillators are a good example of this, where you may need a series resistor to reduce drive levels, so you place a zero ohm resistor to complete the circuit and then if needed you can remove it and solder in a real resistance

Another example is to split a net in your cad software. You may want to split your ground traces by having your digital and analog return to your supply ground by separate paths. You place a zero ohm res near the supply ground and call the other end of it analog ground

[codeboy2k]

I also have used them for board variants, where you have several different spec'd designs from the same board... each variant of the same board may have several components marked DNI (do not install) and you use 0-ohm resistors on that variant to route signals around missing parts, for example.

also, take note of what Robrenz said, these 0 ohm parts have a few mOhm and this threw me off once before I knew this.   

usually it doesn't matter, but in some cases it's necessary to know when 0 ohm isn't really 0.

[Psi]

Sometimes you see them used as cheap and dirty fuses, but its bad practice.

They're used sometimes in complex battery powered devices so parts of the circuit can be isolated by removing the component.
It's useful when debuging and tracking down standby current draw.

[vk6zgo]

I also have used them for board variants, where you have several different spec'd designs from the same board... each variant of the same board may have several components marked DNI (do not install) and you use 0-ohm resistors on that variant to route signals around missing parts, for example.

also, take note of what Robrenz said, these 0 ohm parts have a few mOhm and this threw me off once before I knew this.   

usually it doesn't matter, but in some cases it's necessary to know when 0 ohm isn't really 0.

Unless you can make it from  a superconductor,it never is!

[GamerAndds]

so I was working on an amp once.. very old and noticed a bunch placed along the pwr leads(+- supply) for no reason. I guess    they where suppose to act like fuses of some sort but that's just dirty for the manufacture to do... in fact if remember correctly there was no fuses on that amp (other than mains of coarse)... it was a good one while it lasted... should try and get it working again. I personally
I often feel like getting some  to play with, see about using them as fuses and things.
http://ca.mouser.com/ProductDetail/Yageo/ZOR-25-R-52-0R/?qs=sGAEpiMZZMtlubZbdhIBICXBKsnvdtuN3NAf1v4iscc%3d

one thing, they do look better than jmp`s, especially in a resistor field

[74HC04]

Some zero ohm resistors specs can be as high as 20 mOhms.  Usualy would not cause a problem but be aware.

The ones I've worked with tend to be 50mOhms max and typically only 2A max (size dependant of course). Some can handle higher currents due to metal-based construction.

[babysitter]

How about the tolerance band ? If it says, like, 0 Ohm 10%, whats 0 Ohms minus 10 percent ? 

[SeanB]

20mohms with a spread of 10 to 100 milliohms, and depends on temperature and current.