Post Go back to editing

AD5933: Steep rise in phase

Category: Hardware
Product Number: AD5933

Hi all,

I'm using the AD5933 eval board in order to test an impedance measurement cell. I use shielded cables (30cm) to connect the cell with the board. The cell behaves like a capacitor.

I used the following settings for the measuerements:

Rfeedback: 1M
Rcal: 1M
Start frequency: 3kHz
Delta: 220Hz
511 points
Settling Time Cycles: 15
Upp Output: 1V
Gain: 1
Settling Time: X2
Multipoint Calibration

During my measurements i observed steep rises in the phase for which I had no explanation.

Because of this I installed a 10p capacitor instead of my measurement cell, but it shows a similar result:

Do you have got an explanation why the rise in the phase is that steep?

Thanks in advance!