0 Ohm resistors - Page 1
Forum section: electronics / beginners

author: madmaxbryan
author_rank: Contributor
timestamp: April 08, 2011, 02:25:12 am
content: What is the purpose of 0 ohm resistors? I have noticed a lot lately that most of the boards i assemble at work are using 0 ohm resistors rather then simply using jumper wires. For us the process is exactly the same for both jumper wire and resistors, same axial sequencer/inserter, same wave soldering process, same everything on our end. so wouldn't it be cheaper to use jumper wires rather then 0 ohm resistors?

author: dmlandrum
author_rank: Regular Contributor
timestamp: April 08, 2011, 02:35:42 am
content: I remember someone explaining on another board that pick and place machines have problems placing with little bits of wire, so they make the little bit of wire look just like a resistor and call it 0 ohms. Something like that, anyway.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: April 08, 2011, 03:03:05 am
content: They could be also to make selections, like decimal places on Panel Meters.In the other hand 0 ohm resistor looks much better than wires.

author: madmaxbryan
author_rank: Contributor
timestamp: April 08, 2011, 03:29:46 am
content: as far as i know, pick and place machines cant be used at all for through hole parts, thats why we use an axial sequencer and axial loader. it bends and loads jumper wires just as good as it can for resistors or any other axial component

author: PetrosA
author_rank: Frequent Contributor
timestamp: April 08, 2011, 03:55:45 am
content: 0 Ohm resistor sounds like the kind of oxymoron Kurt Vonnegut or Joseph Heller would have thunk up

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: April 08, 2011, 05:51:47 am
content: Well for true low ohm bridges , only the silver wire can do the trick.But it costs a bit.

author: Simon
author_rank: Unknown
timestamp: April 08, 2011, 06:37:35 am
content: even silver wire will have an infinitesimal resistance. The term "0" ohm resistor really is just saying a jumper in the form of a resistor case

author: Psi
author_rank: Super Contributor
timestamp: April 08, 2011, 06:43:36 am
content: 0 ohms are quite handy when you want to make it easy for areas of your circuit to be disconnected from each other.For example, they quite often put one 0 ohm resistor in each power rail in cellphones (there are often 10 or so power rails for various things). It makes it easy to debug when you're trying to optimize power usage and reduce usage when in cpu sleep modes.You can unsolder a few 0 ohms and watch the overall current to see which area of the circuit is drawing power when it shouldn't be. You can also replace the resistor with some wires and measure the current directly.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 08, 2011, 07:38:51 am
content: Many years ago the Farnell catalogue had some 0R resistors listed with a 5% tolerance spec...

author: madmaxbryan
author_rank: Contributor
timestamp: April 08, 2011, 08:10:56 am
content: so what is the point of using 0 ohm resistors over jumper wires? since a 0 ohm resistor is just a jumper wire with a resistor casing on it.

author: jahonen
author_rank: Super Contributor
timestamp: April 08, 2011, 08:54:40 am
content: For SMD pick and place machines, chip 0R resistors are considerably more suitable than just a piece of wire. Most typical use for them here is to add possibility to easily cut signals when debugging designs if there are uncertainties involved, and they are usually removed at final stages of product development.0R resistors are something like 50 milliohms in reality. I had a case where I had to change 0R jumpers (used for prototype testing purposes) to 10 milliohm resistors (also used in the product), due to that the 0R resistors had inconveniently large voltage drop (three in parallel) for the current.Regards,Janne

author: RayJones
author_rank: Frequent Contributor
timestamp: April 08, 2011, 09:23:19 am
content: Quote from: mikeselectricstuff on April 08, 2011, 07:38:51 amThey also list a power rating too! sort of crazy with "0" entered into the good ol I2R

author: madmaxbryan
author_rank: Contributor
timestamp: April 08, 2011, 09:27:24 am
content: i can understand the usefulness of them in surface mount boards, but what about in through hole boards?

author: Strube09
author_rank: Regular Contributor
timestamp: April 08, 2011, 12:18:01 pm
content: I frequently use "0" Ohm resistors to allow for selecting options on my PCBAS.We have some boards at my work that are all the same layout and software but by populating the board with a 0Ohm in one slot or a 0Ohm in second slot activates powers different hardware or software options. Cheaper and smaller than dip switchesStrube

author: madmaxbryan
author_rank: Contributor
timestamp: April 08, 2011, 12:39:52 pm
content: so heres a picture of what im talking about:I would think it would be cheaper to use the jumper wires they use in that picture rather then 0 ohm resistors.

author: Psi
author_rank: Super Contributor
timestamp: April 08, 2011, 02:25:19 pm
content: i think in through hole boards the zero ohm resistors (actual resistors with one black band) are mostly used as poor mans fuses. ie, intended to be a point of failure that is easy to detect/replace.Another reason maybe that, since the are the same size/shape as normal resistors, they can be used in whatever equipment or gear you might have in production/assembly that uses normal resistors.If you used wire instead you'd have to get it pre-bent to the right width or bend it yourself. Neither option would be as cost effective as a zero ohm resistor which can be produced in huge quantities easily with existing resistor manufacturing gear and meets specific standards on size/width etc..

author: apex
author_rank: Regular Contributor
timestamp: April 08, 2011, 03:46:36 pm
content: In a gadget I built about a year ago, I used zero ohm resistors as extremly low value shunt resistors.Their range is from 10 miliohm to about 100 miliohm.Since my device was self-calibrating, It could use about any resistor given...apex

author: Simon
author_rank: Unknown
timestamp: April 08, 2011, 07:11:30 pm
content: what I don't understand is if there are under 10mOhm resistors why are "0" ohm resistors well over that in some cases ? I mean all you really need is a chuck of copper of the correct size possibly with a paint coating around the middle

author: Zero999
author_rank: Super Contributor
timestamp: April 08, 2011, 08:38:29 pm
content: My guess is the 0 Ohm resistor manufacturers are just covering themselves for the worst case scenario. In real life, they're most likely to be much less than 0 Ohm. 10m Ohm resistors are also normally surface mount and physically larger than some 0 Ohm resistors.

author: Wim_L
author_rank: Regular Contributor
timestamp: April 08, 2011, 10:22:35 pm
content: Quote from: Hero999 on April 08, 2011, 08:38:29 pmNeat! Cheapo two-wire amplifiers, no need to order tunnel diodes anymore

author: RayJones
author_rank: Frequent Contributor
timestamp: April 08, 2011, 11:47:11 pm
content: Add a flux capacitor and the time machine is ready for action.

author: Wim_L
author_rank: Regular Contributor
timestamp: April 08, 2011, 11:56:45 pm
content: They're great for charging batteries too!

author: Simon
author_rank: Unknown
timestamp: April 09, 2011, 06:49:45 am
content: Quote from: Hero999 on April 08, 2011, 08:38:29 pmYou work for Farnell ? first they are 5% on 0 ohms now they are less than 0 ohms

author: Zero999
author_rank: Super Contributor
timestamp: April 09, 2011, 07:57:58 am
content: Quote from: Wim_L on April 08, 2011, 10:22:35 pmLol, I think you probably know what I meant though.

author: Simon
author_rank: Unknown
timestamp: April 09, 2011, 08:03:38 am
content: err not really but I'll pretend i do

author: gxti
author_rank: Frequent Contributor
timestamp: April 12, 2011, 07:03:59 am
content: Quote from: madmaxbryan on April 08, 2011, 12:39:52 pmYou're right, jumpers should cost less than jumpers with ceramic on them. It's possible that some machines can't handle bare jumpers, but if yours can then I've got no clue. You'll have to ask whomever is giving you these designs.Sort of funny how many people in this thread keep offering the same explanation about SMD pick-and-place because they aren't reading...

author: tnt
author_rank: Regular Contributor
timestamp: April 12, 2011, 08:07:27 am
content: Is it easy to find jumpers on reels ?

author: metalphreak
author_rank: Frequent Contributor
timestamp: April 12, 2011, 01:32:04 pm
content: If anyone has ever seen the Atmel ButterFly developement boards, mine came with what was essentially a COM Port socket, with a 3pin header and some 0 Ohm resistors to connect to the board. Only thing I can think of, is that it stops solder from flowing from one side to the other, especially when the axial leads are cut short. It also provides some insulation, if the jumper is going across exposed tracks or other components.

author: madmaxbryan
author_rank: Contributor
timestamp: April 13, 2011, 12:06:06 am
content: Yes, you can find 0 ohm through hole resistors on a tape reel. any axial sequencer and inserter will cut and bend then the same way they would a regular resistor, it doesnt know the difference. if you take a 0 ohm through hole resistor and smash the ceramic off, you will see that its just a straight piece of wire (jumper wire) with the ceramic around it, theres really no resistance other then what little bit the wire itself might have.

author: tekfan
author_rank: Frequent Contributor
timestamp: April 13, 2011, 03:51:47 pm
content: Quote from: Wim_L on April 08, 2011, 10:22:35 pmAre tunnel diodes really unobtainable? I can't seem to find anyone that sells them. Can't even find the once popular 1N37xx series!

author: Neilm
author_rank: Super Contributor
timestamp: April 13, 2011, 07:50:06 pm
content: The main reason for 0 ohm links is to give the designer some flexibilty on the board.If a designer thinks that a resistor might have to go there when the board is tested then the 0 ohm link puts pads where he wants. It can also be used to bypass bits of circuit. For example I have designed a widget that comes in several flavours. If you don't want all the bells - then the circuit is bypassed by fiting the link (and money is saved by not fitting the components. Alternativly, if you want the bell the 0 ohm link is not fitted and the other circuitry is. This will allow a designer to increase the volumes on the PCB and reduce the cost.YoursNeil

author: Wim_L
author_rank: Regular Contributor
timestamp: April 13, 2011, 10:11:25 pm
content: Quote from: tekfan on April 13, 2011, 03:51:47 pmI do think they're still around, but have mostly been replaced by fast IC amplifiers which are somewhat less tricky to use. There are also Gunn diodes which have similar characteristics, but they also seem unavailable through the usual big names. I suppose they're specialty devices mostly used by those with special high frequency needs.

author: ArtemisGoldfish
author_rank: Regular Contributor
timestamp: April 18, 2011, 06:13:54 am
content: Just for kicks,http://farm6.static.flickr.com/5302/5614765792_bac140e704_b.jpgHere's a picture of a board with quite a few 0 Ohm resistors.

author: tekfan
author_rank: Frequent Contributor
timestamp: April 18, 2011, 01:02:21 pm
content: Quote from: ArtemisGoldfish on April 18, 2011, 06:13:54 amWow. That's some very high frequency design right there. You can see that the 0 ohm resistors are used as jumpers to go above the ground planes. Maybe they're even used as extremely low value capacitors. It doesn't take much capacitance to make a big difference in a >10GHz circuit like this.

author: Zad
author_rank: Super Contributor
timestamp: April 18, 2011, 02:46:31 pm
content: Quote from: ArtemisGoldfish on April 18, 2011, 06:13:54 amAs someone who does RF work, can I just say that board is pure pornographic FILTH!

author: House91320
author_rank: Regular Contributor
timestamp: April 25, 2011, 01:04:21 am
content: how would a zero ohm resistor be possible

author: Joshua
author_rank: Regular Contributor
timestamp: April 25, 2011, 02:12:03 am
content: In Dave's latest review of the hot air rework station (Atten?), On the pcb, you can see some 0 ohm resistors.Joshua

author: ciccio
author_rank: Frequent Contributor
timestamp: August 09, 2011, 08:23:14 pm
content: Well, through-hole 0 ohm resistors are simply jumper wires with a plastic (or ceramic) coating in the middle.They are available in reel form, and can be prepared (bent and cut) and eventually inserted in the PCB with the same tools that are used for standard resistors.They were available also as simple pieces of wire, without the "resistor like" body, taped in reels.Many years ago I've seen a machine that, starting from a spool of solid wire, was capable of straightening it ,cutting it to length and bending it to U-shape, ready for insertion.I believe that these machines are still used for large productions, especially for single sided boards, but a simple piece of wire has some disadvantages:- it is difficult to handle (by hand): the "resistor body" type is larger, and is easier to pick-up and insert by hand- it is too lightweight, so it moves up during board manipulation and wave-soldering process (see photos in a previous post: the jumper wires don't look very professional...- for double-sided boards, it can short to top-side copper traces if the solder-resist is damaged.This is the reason that, for low production runs, they use the "resistor-like" type (the one with the single black band). For large production runs, I have no recent experience: nobody makes large production anymore, here in Italy....Regarding "wattage", obviously it has no meaning: it is a simple way to indicate size (yes, they have quarter an half watt types).Why are they used? There are multiple reasons:- on single sided boards, as jumpers to replace a track that should be on component side.Sometimes even in dual-side boards some reasons (difficult routing of tracks, track size, "straighter" way for signal, etc) suggest to use a jumper.- on both single and dual sided boards I've used (and seen other designers use) jumpers (made with wire or with "zero ohm") to leave the possibility of an afterthought, or to allow for different versions of the same boards, or whatever.I've not a great experience with the SMD version, but I believe they are used for the same reasons.Last point:ohm must be written with lower case letters. Upper case must be used for the unit's symbol (in this case a Greek omega, that I cannot write here).The same for volt, ampere, watt, meter, farad, henry, etc...

author: gregariz
author_rank: Frequent Contributor
timestamp: August 09, 2011, 08:54:04 pm
content: Quote from: ciccio on August 09, 2011, 08:23:14 pmI used the old fashioned shorting pins and plugs several years ago. They are still available at places like keystone. But most people design them out these days by simply using multiple layer boards. The other reason would be in high power stuff. I'm working on a high power amplifier at the moment where 0 ohms are just not going to cut it so I've opted for shorting plugs instead.I almost always use 0 ohms on RF designs in order to debug a board during prototyping and usually keep them in during the manufacturing cycle (they cost almost nothing and will help in later debugging of any problems). The reason is that an RF design never comes up without a whole lot of bench work and you need to isolate it section by section until it all works together. Then put the 0's in (quite often I'll use a 1nF cap instead of a 0) and voila..

author: ejeffrey
author_rank: Super Contributor
timestamp: August 09, 2011, 09:06:31 pm
content: One reason to use zero-ohm axial resistors over wire links is that they are insulated. This would be important if you were using them on a hand etched board with no solder mask. Even a commercial product with a nice mass produced PCB may have started out with a hand etched board. It also helps prevent contact with adjacent components, if only by forcing you to space your wire links to accommodate the resistor body.For mass production it helps that they come on reels with the same dimensions as a regular resistor.For hand assembly of manufactured PCBs with solder mask, I don't see a real advantage -- as long as the board actually has the space allocated as it would for a regular resistor.

author: metalphreak
author_rank: Frequent Contributor
timestamp: August 10, 2011, 01:11:10 pm
content: Most of the jumpers they use in single sided boards (the ones without any ceramic package) usually just come in a big bag, and are hand fitted.http://www.goodluckbuy.com/3-10mm-length-u-shaped-silver-tone-jumper-wire-cable-for-breadboard-thick-10000-pcs-.htmlI grabbed a bag of 8mm jumpersThey're perfect for bridging the centre gap on breadboards (2 pin gap between each end)

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: August 10, 2011, 04:22:15 pm
content: Quote from: ArtemisGoldfish on April 18, 2011, 06:13:54 amIt's witchcraft... all of it...