Sonsivri

can anybody tell me how I can measure a resistance of Eathing. that will be very low resistance so how I can measure a resistance of that. Low value resistance.

Hi ALLPIC!
Well, if your issue is measure the resistence earth so you will need a Mega Ohmeter and an less 2 metal bars to connect the instrument and then measure the ohm value, i think i'm not sure but for a good earth the value must be less than 20 OHM.
best regards,
Zero

As low it is as better it's!
Expect to see in good earthing a value below 5ohm.
;-)

Are you looking for something like this?

Earth Resistivity Meter by John M. Stanley

This project is a simple earth resistivity meter. Although it is a four-probe design, it uses a simple DC voltage for generating the ground current instead of an AC current, so it is potentially affected by galvanic errors with the source probes.

This article was originally published in an issue of ETI magazine, and reprinted in the 1981 ETI book "How to Build Gold and Treasure Detectors."

http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=geo&file=projects/erm2/index.dat


Earth Resistivity Meter by Robert Beck

This is a two-part article that gives the construction details for a device that can measure ground resistivity deltas. Such deltas might indicate buried anomalies such as large stones, compacted regions, or conductive targets. The articles also give a good background on resistivity measurement as well as some of the pitfalls to watch out for.

It was published in the January, 1997 issue of Everyday Practical Electronics, a popular British electronics magazine that is owned by publisher Wimborne Publishing, Ltd.

http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=geo&file=projects/erm1/index.dat

mustuva,
               Thanks a lot that's all i am looking for..

regards