AnsweredAssumed Answered

AD5933 measure complex impedances

Question asked by Doungh on Jul 25, 2012
Latest reply on Oct 11, 2013 by musach

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

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