Hi,

I have a question about AD5933 using a current source.

I am referring to AN-843 Howland current source.

In the data sheet, the impedance measurement range of the AD5933 is 100 ohms to 10M ohms, but impedance of LOUD SPEAKER in AN-843 is less then 100 ohm.

When using a current source, what is the impedance measurement range?

Hi Park,

I was referring a circuit similar to this one.

In this case, you need to guarantee that the current thru the max unknown impedance x the inamp gain wont be higher than VDD, and the minimum impedance impedance x current x Inamp gain is around 100mV.

Regards,

Miguel