PMOD Impedance analyser - connections

[AVJ]

Hi,

 

This may be more of a trivial basic/general electronics question than something specific to the board

I recently got a PMOD IA to measure impedance. In addition to the PMOD 8 pin connector, there is an SMA connector to connect the impedance. For calibration of the board (gain calibration), I connect a 100kohm resistor (carbon film resistor) directly between the two connectors. This creates significant variation in the impedance (due to capacitive coupling) i.e I see variation in phase (varying between ~-40 degrees to 5 degrees). I was wondering what would be the best way to connect the calibration impedance (and ultimately the test impedance) to these SMA connectors provided on the board to reduce capacitance.  Some details: I am carrying out the measurement at 30kHz, calibration impedance is 100kohm.

[jpeyron]

Hi @AVJ,

Here is a forum thread where a forum member was able to get all of the functions working correctly. They also posted some helpful setup, calibration and usage hints as well as their code(unverified). I haven't worked with the PmodIA but I do know that there are specific calibration ranges in reference to impedance.

cheers,

Jon