Zero Ohm Resistors - Page 1
Forum section: electronics / general

author: Stephen Hill
author_rank: Regular Contributor
timestamp: March 07, 2012, 11:54:43 am
content: Simple question. What are zero ohm resistors for? Where would I use them?CheersStephen

author: McMonster
author_rank: Frequent Contributor
timestamp: March 07, 2012, 12:08:31 pm
content: Jumping over one or more tracks. They're easy to use with pick and place machines.

author: robrenz
author_rank: Super Contributor
timestamp: March 07, 2012, 12:42:14 pm
content: Just be aware that thier resistance can be as high as 20m Ohm. In most cases that is irrelevant but not always.

author: JuKu
author_rank: Frequent Contributor
timestamp: March 07, 2012, 12:54:18 pm
content: Configuration optionsDuring development to isolate circuit sections, when you are not quite sure about best way to do something etc.

author: BravoV
author_rank: Super Contributor
timestamp: March 07, 2012, 01:01:39 pm
content: When the resistance of the copper trace is not good/low enough... j/k

author: robrenz
author_rank: Super Contributor
timestamp: March 07, 2012, 01:14:55 pm
content: Bravo, I know you were kiddiing..010" trace 1oz copper 1206 resistor probably .060" between pads = .0038 Ohm 5 times less than the possible .020 resistance of the "Zero Ohm"

author: wkb
author_rank: Super Contributor
timestamp: March 07, 2012, 02:15:38 pm
content: Quote from: robrenz on March 07, 2012, 01:14:55 pmOnly real men use Josephson junctions instead of plain vanilla frontpanel switches

author: BravoV
author_rank: Super Contributor
timestamp: March 07, 2012, 02:19:17 pm
content: Seriously, when everytime I saw this zero ohm jumper/resistor at a commercially made board, only two things came out from my mind, "uncertainty" + "dead line set in stone", CMIIW.

author: Stephen Hill
author_rank: Regular Contributor
timestamp: March 07, 2012, 02:34:14 pm
content: Thanks for the answers

author: wkb
author_rank: Super Contributor
timestamp: March 07, 2012, 02:56:08 pm
content: Quote from: BravoV on March 07, 2012, 02:19:17 pmDoesn't have to be, could be "multiple product variations selected with jumpers while using the same PCB". Higher production volume PCB -> lower PCB unit cost. The SMD pick 'n place machine does not care about a couple of jumper/0-ohm resistor.

author: BravoV
author_rank: Super Contributor
timestamp: March 07, 2012, 03:00:16 pm
content: Quote from: wkb on March 07, 2012, 02:56:08 pmYou're right, didn't think of that possibilities, thanks.

author: JuKu
author_rank: Frequent Contributor
timestamp: March 08, 2012, 06:30:15 am
content: The developer might have put a few jumpers in to be able to do experiments in development, isolate sections etc. Turns out that the prototype PCB is good to go. The cost of new board revision and two weepks of lost sales buys about a million zero ohm resistors. (Been there, done that...)

author: BravoV
author_rank: Super Contributor
timestamp: March 08, 2012, 06:41:46 am
content: Quote from: JuKu on March 08, 2012, 06:30:15 amSo is this practically falls into category of "uncertainty" + "dead line" (or time constraint) ?

author: metalphreak
author_rank: Frequent Contributor
timestamp: March 08, 2012, 08:22:47 am
content: I've seen many boards that have zero ohm resistors between certain sections and the ground plane. Perhaps to control the current path and isolate some sections? Maybe it makes it easier when doing EMI/RF emissions testing etc if they can isolate parts.In some cases, it can make for a cheap fuse

author: T4P
author_rank: Super Contributor
timestamp: March 08, 2012, 10:40:17 am
content: Quote from: metalphreak on March 08, 2012, 08:22:47 amI see them used mostly as jumpers .

author: ciccio
author_rank: Frequent Contributor
timestamp: March 08, 2012, 11:49:53 am
content: Quote from: BravoV on March 07, 2012, 02:19:17 pmI disagree..are we talking about SMD type or leadet ZERO ohm resistors ?The leaded type, it's a simple jumper of solid wire, and it is more easy to cut and bend with the standard equipment and place by hand.I use a lot of them, in single sided boards, and maybe with a more accurate design work at time of PCB drawing some of them could be omitted, but:- they allow to avoid too complicated tracks routing.- most of the time the PCB has less problems in operation (shorter tracks are always better, in my applications, etc..).- they are really inexpensive (but they cost more than a resistor of the same size) and time to production may be reduced, but everyone does his accounting..Seen as a fuse, I think it could be rated at tens of amps... no use as a fuse.I've learned from experience to never trust on current carrying capacity of PCB tracks.. a solid link of wire has better capacity of a standard-size track.SMD type are different, theyr current capacity is limited..Beware of some unmarked SMD inductors that are similar in appearance to resistors, and measure a zero resistance: they are inductors, not resistors, and sometimes thy are used to limit EMI and, yes, they will burn if their rated current is exceeded.Best regards

author: metalphreak
author_rank: Frequent Contributor
timestamp: March 08, 2012, 03:00:53 pm
content: Yes I meant SMD ones as "fuses" as in when things go terribly wrong outside of expected operation.Jumper links without the resistor "body" on them (as in just bent pieces of wire) can be had in bags of 10,000 for about $20. Surely this is cheaper than boxes of leaded resistors? They're also great for use on breadboards for making short linksIn most cases I would say they're most useful as jumper links. After ripping apart an old laser printer, I noticed every (signal) section was tied to the main ground plane via 0-ohm smd resistors.

author: Colfaxmingo
author_rank: Contributor
timestamp: March 08, 2012, 05:59:32 pm
content: Has anyone tried to use these for a current sense resistor with any kind of success?

author: Unknown
author_rank: Unknown
timestamp: March 08, 2012, 06:03:33 pm
content: Quote from: metalphreak on March 08, 2012, 03:00:53 pmCan all pick-and-place machines handle these wire jumpers? All of the through-hole ones can handle 1/4 W resistors.

author: wkb
author_rank: Super Contributor
timestamp: March 08, 2012, 07:01:45 pm
content: Quote from: alm on March 08, 2012, 06:03:33 pmCould very well be a problem. I know we used to use the ones with bodies in our machines. I do not expect the bodied-ones to be much cheaper by the way.

author: metalphreak
author_rank: Frequent Contributor
timestamp: March 09, 2012, 08:07:45 am
content: Nah these ones would be for hand assembly I guess. They're just loose in a bag.http://www.goodluckbuy.com/images/detailed_images/sku_73067_2.jpgYou see them a lot in the dirt cheap single sided boards - power supplies etc

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 09, 2012, 09:44:13 am
content: Quote from: BravoV on March 07, 2012, 01:01:39 pmif its possible, then how many jumpers are you willing to use as "copper trace" replacement?i've seen several cheapo/clones that put 0ohm jumper instead of other eligible part, such as replacing smd ferrite (emi and transienst suppresion i guess).

author: BravoV
author_rank: Super Contributor
timestamp: March 09, 2012, 10:05:49 am
content: Quote from: Mechatrommer on March 09, 2012, 09:44:13 amHere, lesson in internet lingo ... j/k = just kiddingYou're loosing it Mech.

author: SeanB
author_rank: Super Contributor
timestamp: March 10, 2012, 10:41:07 am
content: I have seen modern single sided boards with hundreds of jumper wires, instead of a double sided board. Done I suspect to enable use of a cheap SRBP board, and links that outnumber the other components, with rows of multiple links jumping wires across the board. A double sided board with through holes would probably be cheaper for a few dozen boards, but a single sided board made in a press will be cheaper if you are making thousands of them. A old copier had a board with about 30 links per component on it, it had more length in links than copper traces.