Conductance test

[rauldm]

Hi, I have good multimeters from Fluke and keysight, recent add to my bench a Hioki DT4253, I found this meter new a amazing price,I couldn't leave to buy it. Hioki has incredible auto range, ultrafast continuity, even I think is more fast than my fluke 87v or 179, I have 289 and u1282a, but I think these meters are to slow, even u1282a is more slow than 289, this week I found a Hioki DT4281, but is missing A terminal and nS function because is for  electrical use , here start the proposite my post, is not common for me use nS function, but in this days I use this function for understand its functionality, the u1282a can measure up to 600 nS,  around 1.6 Mohm, this meter can measure up to 600 MOhm therefore I think the 600 nS range is not functional I'm wrong? I think the conductance test is more functional in low value ranges because is more closet to high resistance values, but under 1 nS range the lectures are very unestables, I think the more correct  application of conductance test is for measure resistors more than 500 MOhms for example.
Conductance test also is not applicable for  Insulation test  because you need apply a high voltage to stressing insulation of electric machines. Even insulation test can't contemplate parasit capacitances in insulation, I use  leakage current test  this case and insulation resistance is more low even.

Based in this I decided testing conductance in a Diode for found other use.
 Testing diode is 1N5399(up to 1000 V reverse voltage), with 5 multimeters  and insulation tester.

U1282A
conductance test 1.54 nS around 649 MOhm
resistance test   645 MOhm
Fluke 289
conductance test  0.66 nS around 1.51 GOhm
resistance test  OL
Fluke 87V
conductance test 0.41 nS
Resistance Test OL
Fluke 28II (similar ranges to 87V but different open circuit voltage)
conductance test 1.62 nS
Resistance Test OL
Agilent 34401A (not conductance, but wide range for resistance test)
Resistance test OL
Finally
Fluke 1507 insulation meter
1000V test, >11.0 GOhm, out of range also.

I think the conductance test is in function of  open circuit voltage in multimeter, u1282a and 28II it has similar values because open circuit voltage is around 3V, Fluke 289 and 87V has 5V and 7 V respectively, but when apply a true high voltage with insulation meter can apresiate the conductance measures in multimeters is not coherents, the result  would be more  low resistance value with insulation meter because the test voltage is closet to inverse voltage in diode.

Conclution, I think the conductance test is not esential in multimeter.  I hope your comments
Regards.

[Trader]

Very good point and experiments, thanks.