waveforms reference resistor setting

[LHji]

I ahve two questions about the impedance analyzer in Waveforms.

1.  The meaning of Rs, Xs, Rp Xp vakue? I assume Rs and Xs are the impedences of R and C(or) L connected in serial, and Rp and Xp are the impedances of R and C(or) L connected in parallel.

2. How can I change the reference resistor ro a large one than 1 Mohm?  My DUT has a capacitor ~200pF and parallel resistor ~10G ohm.  I think we need a ~10 Gohm reference resistor for accurate impedance measuring in 0.01Hz to 1 Hz range.

Thanks

[JColvin]

Hi @LHji,

Rs and Xs are the series resistance and reactance, respectively. Rp and Xp are the parallel versions of the resistance and reactance. You can verify this by viewing the tool tip while hovering over their icons in WaveForms (or viewing their definitions in the Impedance section of the Help tab).

I know you can adjust reference resistor values by clicking on the word "Compensation" in the Impedance tool itself, which will let you manually type in resistance values and perform compensation for those exact resistances, but it appears that the largest you can type in is 1 GOhm. I will let Attila comment on the feasibility of using such a large (or larger) resistance with this system.

Thanks,
JColvin

[attila]

Hi @LHji

The reference resistor value can be change as shown by James up to 1G.
Note that the Scope inputs have ~1M resistance. This doesn't matter on the W1 side but on the other side it will be in parallel with Ref (or DUT). The DUT will be referenced to Ref|1M so it doesn't make too much difference having ref above 1M.

Specially with high reference values, make sure to perform open compensation.
Here it is a measurement with 100pF and 10M5%, the highest value I could find.