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Comment by tyingq | Hacker News Reader

>0 ohm resistors

Had me scratching my head for a minute there. I guess it's a thing now, though we used to just call them jumpers.

They've been around for decades, both for thru-hole and surface-mount. When you're using automated machinery, you don't want to mess around with wire jumpers; a zero-ohm resistor can be inserted or pick-and-placed using the same automated equipment that normal resistors are placed with.

It's just a funny name to me. Zero ohm and resistor are mutually exclusive.

To me, it's still a jumper, shunt, etc.

Ah, but the trick is to get the low tolerance ones. Two reasons: A) then it’s +/- 20%, right? Which means you bucket them and resell the + ones, using the rest to mine crypto, and B) you save money because 5% of 0 is no more than 20%.

It's also physically impossible for it to actually be 0 ohms. Unless there are consumer grade superconductors that I didn't know about.

That's why 0 Ω resistors have a current rating.

They're rarely just jumpers, they're often fuses as well because they have a current rating. 0 Ω are sometimes uses as sacrificial fail safes when there's not a cost budget for thermal self-resetting fuses such as those used in automotive applications. And it's usually cheaper to bridge two pads with a blob of solder than maintain and source another part in the BOM.

I suppose, though, if you look up those ratings, they aren't terribly different from the max current ratings of a copper wire with roughly the same cross-section area.

Well a wire also has a current rating, I guess that's a fuse aswell?

"Fusible link wire" exists - it is sometimes used in automative wiring harnesses (mostly older vehicles I think).

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