Steve,

If you go to the website of the Society of Exploratory Geophysicists(http://www.seg.org),click on Publications, then goto the Geoarchives, choose the year 1997, then select the Sept.-Oct. issue, go down to the bottom of the list of Papers and about third or so from the bottom is the paper titled "Some case histories of source discrimination using time-domain spectral IP" (which will be in pdf. format). This paper describes Induced Polarization and in particular its use in finding Gold deposits, which is what I'm interested in. I had circiut boards for an earth resistivity meter made and now I need the capability to measure the fall time of the return pulse generated by it . Any help would be greatly appreciated. If your interested in building your own Metal Detectors (Pulse, VLF,BFO, etc.) or this earth resistivity meter, check out this incredable website for the free plans at http://tthn.com/geotech.

Randall Seden