Input impedance in Fluke autoranging meters

[e61_phil]

Sorry, I'm not allowed to post photos.

The setup isn't very special. A 3458A, a 34470A and a FuG high voltage supply (HCP series with high stability and low noise options). Everything is connected with coaxial high voltage cables and 10kV-SHV Plugs. The HV probes are simply connected to a wire which is soldered to a 10kV-SHV jack.

The DIY 1000:1 divider is built up of 20 selected Caddock USF 371 resistors and a 100k Vishay S102 (or Z201?)+some Rhopoint PWW for fine tunning. Worst case uncertainty calculation gives about 35ppm at 10kV, but it seems to be much better.

[FlexibleMammoth]

I'm genuinely amazed by the precision of the Testec probes. With fluke, it seems some kind of lottery - you may or may not get lucky...

Thank you so much for the 50mv/500mV measurements. I do not have the means to do these at home, probably need to take my meter to the lab at university. Now I have something to compare to! 

[HighVoltage]

The DIY 1000:1 divider is built up of 20 selected Caddock USF 371 resistors.

Wow... they are 30 Euro a piece !
Is that correct?

[FlexibleMammoth]

The DIY 1000:1 divider is built up of 20 selected Caddock USF 371 resistors.

Wow... they are 30 Euro a piece !
Is that correct?

Well as he can't post pictures, this is a cal lab/workplace/whatever. I doubt they care if they can afford both a 3458A and a 34470A   

[HighVoltage]

Wow... they are 30 Euro a piece !
Is that correct?

Well as he can't post pictures, this is a cal lab/workplace/whatever. I doubt they care if they can afford both a 3458A and a 34470A   
[/quote]
Well, I also have a 3458A and a 34470A and know about expensive equipment. Somehow I just did not expect this high price for this resistor. But I guess one has to spend the money to get this precision divider.

I have a few Tektronix high voltage probes P6015A and a couple Fluke 80K-40.
It would be nice to have such a precision divider to check the calibration of the probes.

 

[FlexibleMammoth]

Well, I also have a 3458A and a 34470A and know about expensive equipment. Somehow I just did not expect this high price for this resistor. But I guess one has to spend the money to get this precision divider.

Mark me down as impressed and envious :-)

It would be nice to have such a precision divider to check the calibration of the probes.

You're not the only one there!
Is 30 bucks for factory-preselected resistors? If not, that setup might have cost even more...

[fcb]

Sorry, I'm not allowed to post photos.

The setup isn't very special. A 3458A, a 34470A and a FuG high voltage supply (HCP series with high stability and low noise options). Everything is connected with coaxial high voltage cables and 10kV-SHV Plugs. The HV probes are simply connected to a wire which is soldered to a 10kV-SHV jack.

The DIY 1000:1 divider is built up of 20 selected Caddock USF 371 resistors and a 100k Vishay S102 (or Z201?)+some Rhopoint PWW for fine tunning. Worst case uncertainty calculation gives about 35ppm at 10kV, but it seems to be much better.

Such a shame about the pix.

I looked up FuG - their gear looks amazing. Very cool that they can build a 100+ person company making that stuff.

[HighVoltage]

I looked up FuG - their gear looks amazing. Very cool that they can build a 100+ person company making that stuff.

Yes, FUG is an amazingly good company. And when I repaired my 12.5 kV unit, I got all the support I needed, although this instrument is out of production for a long time.

[emg]

thanks for your answer.
My HIOKI clamp meter and UNI-T DDMs seems to use similar divider therefore having variable input resistance. 

[EC8010]

I just checked my Fluke 89 IV direct voltage ranges and got 10.991M, 10.092M, 10.002M, 10.002M.