| Products > Test Equipment |
| Review and tear-down of UNI-T UT612 LCR meter |
| << < (5/21) > >> |
| Wytnucls:
I didn't say 4 jacks, but 4 wires or 4 traces on the PCB going to the 2 input jacks, not the guard jacks. The CEM only uses 2 traces. After proper calibration, there would be extremely little difference between measurements with Kelvin clips and the UNI-T adapter. I think you have a wrong conception of what Kelvin clips are for. There are really useful to measure small resistance at a distance, which do require long leads to the DUT. In other circumstances, with very short electric paths to the DUT and proper meter calibration, measurements would be essentially the same. I don't know how many people actually need the Kelvin clips feature. |
| alm:
The long leads you can compensate for, their resistance is constant. Kelvin connections are critical once contact resistance between the probe/clip and DUT becomes significant. This contact resistance often varies between measurements, and may be dependent on force. Kelvin connections can compensate for this variation. |
| Spawn:
Thanks for the review Wytnucls, this one is looking really nice with its case and all. The one I reviewed was low end for sure, this reminds me the difference in the insulation testers I got, UT501 and UT511. If you want quality with Uni-T you have to pay more for it, but the price is still good on the market compared to other equipment makers. |
| BravoV:
--- Quote from: Wytnucls on March 07, 2013, 08:09:44 pm ---I didn't say 4 jacks, but 4 wires or 4 traces on the PCB going to the 2 input jacks, not the guard jacks. --- End quote --- Wytnucls, assuming I don't mind voiding warranty by doing some minor surgery and do some mod at the connectors, is it possible to have 4 wires Kelvin clip ? I can't see clearly at the board detail at the input section from your board photo. |
| Wytnucls:
Here is a better PCB picture, with a close-up of the jacks. At first glance, it seems possible to modify for a proper 4-wire measurement system. You would need to investigate further, before you start hacking at your meter. I think you would be better off buying an LCR meter with the 4-wire function out of the box, if you desperately need that feature. I personally think Kelvin clips are a bit overrated on a low resolution machine like this and I bet you won't see any dramatic increase in accuracy, after your modification. Nevertheless, it might be easier to use the 'Guard' jacks for the 2 additional 4-wire connections, as a guard connection is only useful if you measure a resistance above 10 MOhms anyway. If you want to keep a 'Guard' connection, it would be relatively easy to install a fifth jack with a PCB plane connection for that purpose. |
| Navigation |
| Message Index |
| Next page |
| Previous page |