Hi all,

I am going crazy with this AD5933 chip. Now i am measuring the impedance of a complex circuit. A parallel RLC circuit.

I am confused in designing of rfb and rcal, i know to design the rfb,rcal for resistor alone,capacitor alone and inductor alone,rc,rl.

Here for rfb=rcal=100k,

**RMIN=80K ,RMAX=220K**

**CMIN=7.2E-11 CMAX=1.99E-11**

**LMIN=12.73 LMAX=0.35**

**Is this correct??**

**Is there any other formula to calculate both rfb and rcal for RLC circuit???**

Now my set up is

Here i am sweeping the frequency from 10k to 100k and rfb=100k and rcal=100k

Now i am measuring R100K,C=33pF,L=2.3mH

But in inductor case L i used is 2.3mH which is out of range still i am getting perfect answer for Impedance.

**So i am confused in RLC measurement range!!!!**

Regards,

Sony Sunny.

Hi Sony,

You should calculate your impedance range max/min, based on the range of impedance you are going to use.

Once this is done, you can refer to this AN to calculate RFB and Rcal.

http://www.analog.com/media/en/technical-documentation/application-notes/AN-1252.pdf?doc=cn0349.pdf

Regards,

Miguel