When and why are 4 wire cables useful for measurement, apart from power supplies

[cdev]

Can anybody explain this in a few words or point me to a resource that lays it out? I'm particularly curious about what the scenarios where the four wire measurement would make a significant difference in the measurement, that isnt accounted for by something like a "relative" zeroing function.. . I'm familiar with how voltage drop in a cable can and does make a big difference.. I guess thats the situation I am most familiar with, especially when cables are undersized for the load.

lets say with tuned circuits.. would the ability to do four wire measurement help me learn what makes a coil or capacitor appropriate for a specific application (to have high Q?)

(getting rid of losses in a tuned circuit to increase its Q) - I already have a multimeter with a adequate amount of resolution for 95% of what I do but its not so great for measuring really low resistance.

I can see now how different surfaces behave a lot differently in terms of resistance measurement repeatability, Would four wire measurement help there? Why? This is just one of those dumb things that I find myself wondering about a fair amount that I haven't found a really good explanation for anywhere.

Thank you!

[MosherIV]

Hi

Just like 4 wire for psu, for meaurement it reduces or removes the effects of the measurement leads.

It makes a huge difference when meauring very low or very high value resistors.

It also makes a difference for L or C, cancels out lead impeadance.

Hope that is simple enough for you and helps.

[TimFox]

Yes, 4-wire connection is best for low resistance values, but of little value for very high resistance.

[ruairi]

It bears repeating that if you are thinking of buying a set of 4 wire leads that Franky's kit is excellent and great value, mine has been in almost daily use since i built it 3 months ago.

[w2aew]