LCR output is pulsing sine wave on then off why? - Page 1
Forum section: electronics / testgear

author: accesscontrolforum
author_rank: Contributor
timestamp: January 20, 2016, 04:34:16 am
content: had a quick question about the output of my LCR an Agilent U1731B. It shows a 1K sine wave for one second and then DC for one second. Is this how an LCR output is supposed to look? If so why does the signal turn off every other second? Or are my measurements just wrong? Thanks for your opinion and help.FYI this video is unlisted and not monetized (for now). I don't want anyone to think I am trying to get hits because Dave's forum is so big.

author: cat87
author_rank: Regular Contributor
timestamp: January 21, 2016, 09:47:57 am
content: This is just a hunch I have, but I think it's OK for the measurement waveform to be like that. I've searched for some details on how these meters from agilent...er, keysight make Impedance measurements, but couln't find anything.There are several methods one can employ, to measure complex impedances.For example, a Peak Atlas LCR45 has a positive spike, then a negative one and after that a few periods of a sinewave and that's it.If you could also add a pic of the waveform, that would be of even more help and maybe other more experienced people can give you a definitive answer.

author: accesscontrolforum
author_rank: Contributor
timestamp: January 21, 2016, 03:06:51 pm
content: The link above is a video and it shows the waveform. Thanks cat

author: CustomEngineerer
author_rank: Frequent Contributor
timestamp: January 22, 2016, 01:27:12 am
content: I have an Agilent U1733C LCR and it does not pulse regardless of frequency selected or test performed.Edit: I should probably note that I did the test with a double banana jack to bnc adapter on the meter, and a probe to bnc adapter on the probe. So the meter was just reading the capacitance of the probe/scope. Are you sure that the meter is causing the pulsing and not something else in your setup?

author: accesscontrolforum
author_rank: Contributor
timestamp: January 22, 2016, 02:09:13 am
content: Custom. I want That LCR so bad!!!! One just dropped from 350 to 330 on ebay, but im cheap.I'm using the probe that came with my scope. Here's how I have it set up. it just so happened that I caught my scope right in the middle of the reading half on half off. Thanks for checking with your meter.Also I have replaced the battery. it does the same in parallel or series.It seems to output a similar sine wave for second then off for second even On resistance and capacitance. Which makes sense if it's checking impedance but I thought It would output DC for resistance.thanks

author: CustomEngineerer
author_rank: Frequent Contributor
timestamp: January 22, 2016, 03:09:56 am
content: I didn't think the B series would do DC Resistance measurements. I'm pretty sure the R of ZLCR is an AC Resistance measurement. If so it would still show and allow you to select the frequency. The C series do have a dedicated DCR (DC Resistance obviously) measurement function that does put out a steady 1V DC signal (actually measured it at about 1.2V). On the C series you can switch to the DCR test by holding down the frequency button for a second.Don't get me wrong, I really like the 1733C, but ever since I got it I've been wishing I had gotten a DE-5000 LCR Meter instead. It can do everything the (as far as I know) the Agilent 1733C can (including 100 kHz) but it only cost around $100 and can do 4-wire measurements. I'm sure the Agilent probably has better accuracy and I believe an extra digit of resolution, but not sure that quite makes up for the $300+ price difference. I know I could easily sell the Agilent and have plenty to pick up a DE-5000, but since I already have it, enjoy it and know it works great I can't seem to bring myself to part ways with it.Edit: Meant to add that I did another test with the probe and meter hooked up exactly like in your picture and still get a steady sine wave with no pulses in every mode except DCR.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 22, 2016, 03:29:20 am
content: http://icom.hsr.ch/fileadmin/user_upload/icom.hsr.ch/publikationen/RLC_Meter_EN.pdf

author: accesscontrolforum
author_rank: Contributor
timestamp: January 22, 2016, 03:29:53 am
content: Thanks for the info. never saw the DE-5000 Handheld LCR Meter. You are right the freq is selectable in the 1731b for resistance. Should have thought that one through.

author: CustomEngineerer
author_rank: Frequent Contributor
timestamp: January 22, 2016, 03:44:01 am
content: I had thought the same thing. I didn't realize it was using an AC signal for the R measurement until the first time that I actually used the DCR measurement function. Until then I wasn't sure why it had both the R mode and DCR mode.

author: ahakman
author_rank: Regular Contributor
timestamp: January 22, 2016, 11:03:20 pm
content: It's clearly because you hooked and Agilent LCR meter up to a Rigol scope - the Agilent pixies and the Rigol pixies don't dance well together--Keep yer stick in a vice!

author: CustomEngineerer
author_rank: Frequent Contributor
timestamp: January 22, 2016, 11:59:29 pm
content: The pixies in my Agilent LCR meter and Rigol scope did the dance. You think maybe they did it just to spite me?

author: accesscontrolforum
author_rank: Contributor
timestamp: January 23, 2016, 01:05:13 am
content: I talked to a buddy of mine, who's in the know, he says that Agilent's and Rigol's electrons are compatible but Keysight's and Rigol's are not. So I should be good there, any other suggestions?