Galvanic Isolation Help

Discussion in 'The Projects Forum' started by JCafone1, May 6, 2009.

  1. JCafone1

    Thread Starter New Member

    Apr 28, 2009

    I submitted a thread not too long ago regarding patient isolation:

    "I am currently working on a project to measure complex impedance. This is done by introducing a current (~1mA) @ various frequencies (1k to 1M Hz). I would like to float all components in contact with the load. To do this, I would like to use an opto-isolator do to their availability and cheapness. I am having problems locating one for my specific use. Any suggestions?"

    I have not really received helpful responses or solutions to the problem. I just realized that the lab I am working in has an isolation transformer power station. Therefore, if I were to plug the output and input of the circuit into this power jack, does it provide isolation to the load? I will power the rest of the equipment using batteries. The circuit would be as follows:

    Power>Isolation Transformer>Function Generator>Current Limiter>Electrode In>Patient>Electrode Out>Instrumentation Amp>Oscilloscope>Isolation Transformer>Power

    Essentially all items in bold would be referenced to a floating ground as compared to the input Function Generator and output Oscilloscope.

    Is this valid? If not please explain. Thank you!
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    The power isolation transformer provides isolation from the mains. It cannot isolate your bold-print items from your standard-print items.
  3. nanovate

    Distinguished Member

    May 7, 2007