| Products > Test Equipment |
| Review and tear-down of UNI-T UT612 LCR meter |
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| nadona:
Thank you very much for the awesome review. You created the spreadsheets the same way I would have, with all of the parameters/data desired. The photos are also very useful; they are taken in a way that I can grasp the real-life size of the parts. After reading your review, I made one click on eBay without a second thought, and purchased one for $153 including shipping to California. Regards. |
| Wytnucls:
Thank you for the kind words. I sure hope you won't be disappointed. Unfortunately, I don't own shares of the company (UNI-T is a privately-held company, with the owner based in Hong Kong). Let us know later if the meter lived up to your expectations. If enough people are interested, PM Franki first, as he can probably beat that price with direct sales to members of this site. http://stores.ebay.com/99centhobbies |
| Wytnucls:
I had a look at the IET logging software. It is more sophisticated than the UNI-T program, with mostly better control of the graph display scales and a proper manual trigger control on key F12. It is freely available on the IET site, if anybody wants to have a trial run. And, no, it is not compatible with the UT612. :) Of course, it comes at extra cost, as it needs the dedicated USB LCR meter hardware interface connector to work properly. Incidentally, IET doesn't give you proper 4-wire Kelvin clips with their meter either. You will have to buy those separately or modify the standard crocodile ones. SMD tweezers are also available, but I don't think they are proper 4-wire Kelvin to the tip, only to the handle. |
| PA4TIM:
--- Quote --- Just install the UNI-T software that came on the included CD (unlike the IET) --- End quote --- My IET came with manual and a CD with software, but I have bought it including the USB interface, tweezers and psu. The IET had several connectors. The blade connectors are true 4 wire. the adapter you can push in there forthectweezer or croc leads are using that 4 wire connection. The adapterd uses 4 guarded wires ( technical speaking the IET is 5 wire) to go to the croks, but the croks are not 4 wire ( they are however one best made croks I have ever seen) the tweezers are 4 wire upto the start of the tips, so the last cm or so is not 4 wire but that is more then good enough. The guarding is more important in my opinion as that last cm ( doing L and C measurements) I found one strange thing in the IET, the banana jaks are true 4 wire jacks, so you could use 4 wire if you had special bananas ( that AFAIK do not excist) but in that case the blade connectors make still contact and so cancel your 4 wire connection. The strange thing is non of my bananas fit, the holes are just smaller in diameter. So they made special 4 wire bananas that can not be used for 4 wire technic because there are no bananas that fit and if there were bananas, the blade connctors would short out the 4 wire connection. I just made a small alu box with 4 banana jack, 4 bnc sockets and a lemo connector and a guard connector. All parallel so can be used as in or output. I have two hirshman probes that could be opened. I made 5 connctions using 2 lemo multiconductor wires from a lemo plug to both probes. Only the last 2 cm is one wire. I used these because they are low thermal and the tips are a mix of bananajack and probetip. So multifunction. I have good kelvinclips but not ith guarded wires. I will replace the wires with 4 x RG 179 and bnc so it will be true 5 wire. The banana jack will be used to connect to a 4 wire multimeter, and i make a cable that goes from a bridge 3 wire system to the IET 5 wire system. To connect it to the IET i am still in doubt. I think I make a small adapter using pcb like the original adapters and the 4 guarded wires to the lemo socket or to the bananas. Or ad a lemo socket to the IET adpter and mount the existing crock wires to a lemo plug. Then I can use a lemo-lemo cable to connect the adapter to my 4 bnc adpter. I must do some tests what gives best results. |
| Wytnucls:
Thanks for that information about the IET LCR meter, PA4TIM. It seems that IET didn't take that 4-wire measurement very seriously either. As Alm pointed out, a major benefit of the 4-wire system is to cancel out most of the errors generated by contact resistance between DUT and test gear. So croc pincers or tweezers with only 2 contact points don't really qualify as precise 4-wire systems. At least, with the DE 5000, you have the option to improve on the standard IET gear, by making your own Kelvin clips or tweezers, using the 4-wire blade connections. As far as I understand, the guard connection is only necessary for resistance measurements above 10 MOhms and may have little effect, if any, on L and C measurements. |
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