Products > Test Equipment
IET LOM-501A Micro Ohm meter
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SeanB:
Lovely technique, like the isothermal block you made, and the nice simple ways used. Very nice, makes my measurements look crude. All I can get is a 10mOhm resolution on a 10R resistor, but it is not 4 wire, just a bridge.
robrenz:
I finally figured out how to convert excel to pdf to jpg so I could post the low Ohms comparison chart as a picture.  Also added the Keithley, Megger, and AEMC to round out the comparison.  Chart is % of reading error values.  8846A and 34411 are identical above 13 Ohm.  It is interesting to see they all have thier strengths and weaknesses. I would put the 34420 as the winner and the LOM-510A as second for the 1 Ohm to 1 mOhm span.

Max. drive current and resolution.
MEGGER DLRO 10  10A drive  0.1u Ohm resolution
AEMC 6250            10A drive  0.1u Ohm resolution
KIETHLY 580     100mA drive   10u Ohm resolution
LOM-510A              1A drive   1.0u Ohm resolution
AGILENT 34411    1mA drive  100u Ohm resolution
FLUKE 8846A       5mA drive    10u Ohm resolution
AGILENT 34420  10mA drive   0.1u Ohm resolution
AGILENT 3458A  10mA drive    10u Ohm resolution

andyb:
Wow! What is that resistor decade box? Did you make it? I googled a bit for Versa-Ohm, and came up empty.
robrenz:
I was wondering how long it would take for someone to notice that.  It is my own design and name.  I did the  same thing you did, I thought up a name and then googled it to make sure no one else had used it. It is TWO 8 decade units in one box. The resistors 10 ohm and up are 0.1% .25 watt 25ppm and are heat sinked. The heat sink fins are on the back and that is why it is sitting in that orientation for optimum convection cooling.  It also has a forced fan cooling attachment for higher accuracy or dissipation. All the individual decades are available separately so you can get many resistance values out of it simultaneously with supplied calibrated jumpers.  Special jumpers allow paralleling up to 20 resistors to get down to .01 ohm at 5W.  I will be posting a thread/video about all its features soon and there will be a whole series of detailed videos on its design and construction. And yes they will be for sale, I made a first run of 25.  I am just finishing up some of the jumper attachments now.  Stay tuned! :D
andyb:
Very cool! I fall into the camp of folks who've never really seen a use for substitution boxes, but this may change my mind! I'll be watching!
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