Hi,

I’m trying to measure an impedance built up of a resistance R1 in series with a capacitance C1 and resistance R2 in parallel.

The values are as follows:

R1 = 48.7 Ohm

R2 = 200 Ohm

C1 = 0.1uF

When I do the maths I get 71.88 Ohms @ -47.35deg

I would like to think my maths is right…

When I measure this on the chip I use:

RFB = 81 Ohm

F = 30000Hz to 30200Hz

On default gain and settling settings.

The problem is that the chip says my circuit has an impedance of 100 Ohms @ 0deg.

Can you see what I may be doing wrong in this operation.

Regards,

Donagh

Hi Donagh,

Are you using single point or multipoint calibration?

regards,

miguel