http://www.edn.com/archives/1995/033095/07df4.htm
used with a digital multi meter to indicate the voltage level as dc voltage which is equivalent to the RMS value of the RF voltage being measured
http://www.flashwebhost.com/circuit/rfprobe.php
http://www.mrs.bt.co.uk/dubus/9004-4.pdf
An article from Scientific American 1999 about the field mill voltmeter and the results on Earth's electricity.
http://www.sciam.com/article.cfm?articleID=00000ED3-69CA-1C72-9EB7809EC588F2D7
http://www.mrs.bt.co.uk/dubus/8602-8.pdf
information on Hi Pot testing of transformers
http://www.rhombus-ind.com/app-note/hipot.pdf
An online companion for differential equations contains demo notebooks, packages, and links.
http://www.math.armstrong.edu/faculty/hollis/mmade
http://www.ideaconsulting.com/dstrip.htm
for op amp
http://margo.student.utwente.nl/el/analog/opamp02.gif
http://website.lineone.net/~dezellis/images/inteface/inteface.pdf