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Comment by starbeast | Hacker News Reader

Some bit of my head is a zero ohm resistor resistor. Every time I read 'zero ohm resistor', it goes 'nope nope nope' at me.

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It's zero in the number of significant figures used by the test equipment.

That's a pity because then you can't use that resistor to measure current by a measurement of a voltage difference.

They make high-precision low-resistance resistors specifically for current measurement. Your standard cheapo zero-ohm resistor though is more for creating optional connections that you can configure at assembly time.

Think of it as an "epsilon ohm resistor".

Heh, I like that. I tend to think of them as a surface mount jumper.

My 1/4W THT zero ohm resistors are about 0.025 ohms according to my bench meter. In theory, that implies a 400 amp rating... not going to try that anytime soon :)

Why not? They're great as test points and you can pull them off and place a resistor or capacitor in their place.

Probably because the operating temperature is about 0 Kelvin.

I guess it doesn't have to go quite that low, depending on what you make it out of.

Though you have got me wondering whether anyone has put a crumb of high temp superconductor in a smd resistor package yet and if so, for what purpose.

"High temperature" is relative, they still have to be cryogenically cooled to temperatures around -100C. So no SMD superconductors yet.

That is still a relatively accessible temperature, given that liquid nitrogen is about the same price as clean water.

Off the top of my head, I could think of one use, which would be to trigger a transistor to switch on and off some high power superconducting circuit when the small bit of superconductor gets cold enough to start superconducting.

I assume it's the paradox of a resistor that doesn't resist.

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