4 wire kelvin resistance measurement tutorial

How to use the 4 wire (Kelvin) resistance measurement technique to measure tiny resistances (in the milliohm range) using only a cheap multimeter!

[Graham_Wideman]

Thanks for making this modest-seeming video. It's laudably clear and concise, compared to a number of other overly elaborate efforts attempting to cover this same territory. Well done!

[rudyselectronics]

I started with Arduino about 2 years ago. Now I make my own dc lab bench power supply’s. Robot arms. The famous eggduino for Easter. I think you get it. I’ve become absolutely fascinated with electronics and building them. I have used your video’s throughout my journey. They are very helpful. They deal with components and situations I come in contact with on a day to day basis’. Thank you very much for taking the time to talk to use newbies and in a way I, and many others can understand . If you could dive into, and explain how to use, some of these lower end oscilloscopes new people like myself are forced to buy due to financial constraints. I’d greatly appreciate it.

Once again. A large thank you for all you’ve done.

[Serostern]

This is one of the most useful electronics tutorials I have ever seen!

[logano]

Finally made me understand what our shop micro-ohmmeter is for after not being able to "get it." Thanks

[ronplucksstrings]

Thank you for an outstanding presentation explaining 4-Wire low resistance measurement! Knowing sub-Ohm Resistance is an OK theoretical exercise, but I am using this presentation as a reference for explaining practical results when in-line Resistances occur in vintage automotive electrical systems.

[daxweb]

imho, the best electronics tutorials on youtube..
i'm your fan!!!

[mrmacmanu]

Thank you for making this! I adore your videos, they are practical and easy to understand and yet I find them handy for my electronics hobby! Your teaching style is perfect and your humor makes it even better! Thanks and I hope you keep making these! (ps your site is AWESOME!)

[williefleete]

i've made a constant current source using an opamp an a mosfet built into a bench supply i made, it has 6 presets which connects different shunt resistors so i get different current ranges
i've made it so it has 100uA 1mA 2mA 10, 20 and 40 mA, handy for testing LEDs, zeners up to about 15 volts (or high voltage diodes) and 4 wire resistance measurements

[TheCrazyStudent]

I always learn a lot by watching your awesome videos! Thank you for putting them on YouTube.

[Serostern]

@dealio82 Nope, the power supply is capable of running loads of 10amps, the fuse is to protect the PSU from the input current, not the output =)

[FollowTheLion]

You can convert a constant voltage source into a constant current source with a transistor and a resistor. The resistor goes on the base and draws a negligible current, avoiding power resister and regulator.

[ΠάριςΑζής]

8 resistors of 10Ω/0.5W/1% connected in parallel will give you a decent 1.25Ω/4W equivalent, which is perfect for this application.

[silverstream]

Couldn't you use a pot together with the LM317 instead of fixed resistors to tune it to 1A with the multimeter?

[opiatek]

Thanks a lot! I needed to test IR in my Brushless Outrunner Motor, and Now I can do it pretty easily. I just bought LM317 on ebay!

[judgenap]

Yeah ! Dont Stop. Is this the method to measure a coil or a solenoid? Or motor coils?

[tubemasta]

Been a while. Illuminating as usual though. Or should that be electric / electrifying?

[dejayrezme]

Why doesn't the resistance of the wire matter when measuring voltage? Should you get voltage drop as well and basically have the same error from the wire resistance?

Why don't multimeters implement resistance measuring this way?


Thanks for the video!

[yellowmetalcyborg]

@Serostern Liquid nitrogen doesn't stay cool forever, so I need to measure the resistance of the coil once it warms up, so I know how much longer I can make it run before shutdown is necessary : ]

[drumrocket]

cool video!
but could you explain how this current limitation actually works inside the power supply ?
what circuit is inside it, to do that?

[JiaxinYu]

At 3:02 did you connect the resistor to the test leads? Parallel or series? Cause whenever I turn the knob of current limiter on my bench supply it jumps back to voltage control...