Ruoshui 4090C LCR Meter Review

[@TRONMAGNUM2099]

Great job Bill!

[@wernervanschie]

Thanks! Still liking the ET3240 (thinking about buying it) so I appreciate the little "4-wire" ohms comparison you've done in this video. So even though an LCR meter would be a bit too much for this hobbyist, you answered one of my questions about the ET3240. Thanks!

[@LockdownElectronics]

ET3240 is a nice bit of kit! I ordered some kelvin clips to use with it from AliExpress but they never arrived, then I got the LCR meter!

[@CraigHollabaugh]

After watching this, I purchased the 4091C 100kHz continuous frequency meter. I can write a SCPI program to pull the data. It just happened to be on sale direct from Roushui's Aliexpress store. Thanks from Colorado.

[@pshamlow]

What driver did you use to write your SCPI program?

[@CraigHollabaugh]

@@pshamlow I wrote a little python script that sends SCPI commands over serial port at 115.2K. I wrote the company for the SCPI command document.

[@michelgauvin2473]

There is a voltage selector on the back of the unit, but it only says 200-240V 50-60Hz. Does it also operate at 120Vac 60Hz, even though this voltage is not indicated on the back of the unit?

[@jwrtiger]

Very nice video and good information. I have the East Tester LCR meter which I think is the exact same unit as yours with different color scheme and power button. I liked the demo where you commented on selecting the proper test frequency. Selecting 100 Hz for the smoothing (power Supply) capacitors. I am in the US so I set my test frequency to 120 Hz for smoothing capacitors. I am no expert either and trying to learn new things in electronic testing. One note when you were measuring the 0.1 ohm resistor I did not see you null the lead resistance (REL) on the two probe test leads connected to the DMM. Seems most test lead pairs are 0.2 to 0.4 ohms and by using the REL function I think your DMM would read much closer to the 0.1 ohms without using the 4-wire technique. Also I think your DMM is using DC test voltages for resistors while you had the LCR meter set to 1 kHz. I doubt if that would make any difference in this example but you can set you LCR meter to use DC (0 Hz) by pressing the DCR button for measuring resistors. Again I think you presented a very nice video on the utility of using an LCR meter. Looking forward to new videos from you.

[@99icd]

Good review. I'm trying to build an ESR meter at the moment, but maybe I should just follow your lead and get one of these.

[@Chris-hy6jy]

Can you check the reading stability of a resistor in the 1k - 10k range? On a high quality meter, this should give a very stable reading. Looking at the readings during your review, there appears to be quite a lot of instability. Possibly using a low quality ADC or they have noise on the measurement circuit PSU rails?

[@creativebayo9201]

Is it possible to achieve a degradation mechanism for an electrolytic capacitors using an LCR meter by either considering a thermal or voltage overstress. I am aware one can adjust the voltage for the DUT of the LCR meter but is it possible to have the capacitors placed in an oven and measure with the LCR meter continuously. I look forward to your response.

[@mrbambix]

Still debating to buy something like this or to upgrade my multimeter with one that does decent for capacitance and inductance measurments for capicators and coils in ham radio type applications

[@dannytownsend4893]

Will these devices work in USA on 120 volts 60hz

[@inakia.5346]

Where can I download software for this model?

[@Knifeguy6]

i have a question that i cant find an answer too. i have a bench lcr meter and it has 4 connections for the kelvin clip test leads. the meter's test lead connections are marked Lcur, Lpot and Hcur, Hpot. which two connections does the positive test lead connect to? i cant find which test lead goes to which two terminals anywhere.

[@CraigHollabaugh]

I have the 4091C on my bench and the inductance measurements are horribly inaccurate. I measured a 1.6H inductor using a Senncore LC53 (measures at 60Hz). The 4091C measures 7.7MH (which is wildly off). Measures caps just fine. Have you had any success measuring large inductors, 1henry +? Thanks.

[@dandin1862]

That's interesting. I was about to pull the trigger on one of these meters because I need to measure inductance mostly in the range of a few mH all the way up to 15-20H or maybe even higher but now I'm hesitant. Do you still have inaccuracy problems or it was some user error from your side? Thanks.

[@CraigHollabaugh]

@@dandin1862 i worked with their tech support and found the problem, user error. I didn't change the line input voltage switch to 120 for US. Once I did this, my unit worked great. It's a good little unit, simple, fast and easy to use. Thanks for your question.

[@dandin1862]

​@@CraigHollabaugh That's good to hear. Thank you very much for the fast response!​

[@twobob]

Very much liked.

[@joehubler4965]

Great job,