Help on bioimpedance project

Thread Starter

Myshkin

Joined Dec 18, 2012
1
Hey guys!

I have a bioimpedance projetct to make until the end of the year.
I dont know much about the subject in question but i learned the basics and already made some measurements.

I was using two different voltage to current converter source (VCCS) but they were mainly circuits i got on the internet and changed a few.

I was seeking some logical explanation to them and how to improve my project.

The first one
http://imageshack.us/photo/my-images/515/secondproj.png/
The second one
http://imageshack.us/photo/my-images/72/circuit1.png/

Shouldnt the probe in both be giving the Irms value constant rather than I value if we want to measure body bioimpedance (or a simulated body with a resistor and capacitor)?Should i use the I value or Irms, and why, for the measure of a simulated body?

And also shouldnt this current being I or Irms be constant no mather the resistance? something wich is not happening

Im with dificulties in undersanding the concepts behind this howland modified circuits!

What is the output infinite impedance that i see everytime i search for howland circuits applied to bioimpedance?

Sorry for any incovenience.
 
Top