Agilent U1731B LCR Meter Serial/Parallel Mode, Guarding Explanation and Teardown

In this video I explained when to use the serial/parallel measurement modes in the Agilent U1731B LCR meter and why guarding is needed. I also did a teardown towards the end. High resolution pictures can be found on my website at www.kerrywong.com/2018/10/28/a...
Guarding Explained: • Guarding Explained
Dave Jone's teardown of the U1733C: • EEVblog #234 - Agilent...

[@NNITRED]

For the longest time I stayed in series mode and had no clue on what the guard was for. Even in the manuals I see that the knowledge is assumed to be known. Thanks so much for the breakdown. A lot of us needed this video.

[@engjds]

Good video, D is something I forgot about many moons ago, so it was a good reminder, also like the idea of the BNC on there!

[@Mtaalas]

To be exact, the guard should be around the signal wire covering it fully to be really effective. This is also why we use triaxial cables in some testing scenarios: signal-guard-ground.

[@KerryWongBlog]

Yes, I forgot to mention that. Thanks!

[@PapasDino]

Thanks for the guard explanation Kerry, cleared it up a bit for me.

[@KerryWongBlog]

You are welcome!

[@vaidehideshmukh5987]

Very informative. Nicely explained.

[@engjds]

Way I think about series and parallel, if you have a low impedence, the voltage will be very small and the current will be relatively large, so its better to measure series (i.e. current measuring), coversely, for measuring high impedence, the voltage drop will be high and the current will be low, so you measure the voltage across the circuit (parallel). The question is, what is the ideal frequency to measure,? most just think in terms of low and high, to determine accurately, you look at the phase angle at each frequency, ideal components should be purely REACTIVE (opposite to resistors which should only be purely resistive), hence you are looking for a +90 phase angle for inductors or -90 for capacitors or close to it, but measuring one with a +/- 5deg angle means your measured value will be way off.

[@mohbit3336]

Thank you for your explanation I confused the guard port for 3 or 4 wire kelvin measurement but thanks for your explanation and some other research on the guarding topic the confusion is cleared 🙏.

[@KerryWongBlog]

Great! Glad it helped!

[@engjds]

PS: this meter is highly configurable, you can change almost ANY default setting, beeps off etc.

[@aicisha]

Very educative and useful information all across this long video ! Thank you ! Just a small detail: at 25:07 is it a good thing to null out (REL) those 8pF before connecting the plus alligator and doing the actual measurement?

[@Langendimi555]

Thank you!

[@SoddingaboutSi]

Kerry, if you use the ohms range to measure capacitors won't that give you the ESR as the resistance measurements are done with an AC signal?

[@KerryWongBlog]

Hmm, I just gave that a shot. I did get a reading (which is in the ball park of what I would expect for the ESR) back but it differs from the calculated ESR from the dissipation factor? Not sure what's going on here, I guess I will need to investigate a bit more...

[@grhinson]

there is a lot of data and calibration procedures, firmware for the component tester at mikrocontroller. net fyi

[@natarajn5857]

Hi , Escort 133A similar to Agilent U1732B . Error " Fuse" after couple of seconds power ON. Any suggestion for the cause. Fuse good , Voltages Fine. Welcome your suggestions .

[@NiHaoMike64]

Put a piece of tape on the buzzer to quieten it.

[@gordonwedman3179]

Yea, thought of the same "fix".

[@puffinjuice]

put a piece of tape over the hole on the piezo buzzer and the sound will be more gentle

[@fraslinthierry2030]

là au moins un fusible en verre pas comme le beckman 739 avec son fusible smd

www.eevblog.com/forum/testgear/agilent-u1731b-lcr-meter-serialparallel-mode-guarding-explanation-and-teardown/

[@Mtaalas]

I can't open that... you sure the url is correct and it's not patreons only?

[@johnsenchakinternetsecurit8935]

Unfortunately I was censored on the forum

[@Mtaalas]

@@johnsenchakinternetsecurit8935 Umm for what reason?

[@stevenbliss989]