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earth tester

every body ! kindly ;show me the way that I can design my own earth tester,I need to a circuit diagram.

Reply to
mansoor
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Test for what?

Continuity? Static discharge safe limits? Salinity?

RL

Reply to
legg

thanks . to measure soil resistivity.

Reply to
mansoor

thanks . to measure soil resistivity.

Reply to
mansoor

Perhaps the references on this page may be useful:

formatting link

Reply to
John Popelish

** So you want an electronic soil analyser ?

These Google Groupies are such a hoot.

.......... Phil

Reply to
Phil Allison

How far down into the soil do you want to be able to see?

Do you want a profile or just a single value?

Is your local mains frequency 50Hz or 60Hz?

I'll assume 60Hz

(1) Make a good 30Hz square wave that is isolated from any other earthing. This needs to be about 25V and able to output several amps.

(2) Make a synchronous detector circuit. Followed by a filter that cuts off at about 0.5Hz.

(3) Sync the detector (2) to the generator (1) via an opto isolator.

(4) Drive large spikes (1cm Dia 20cm long) into the soil like this

ASCII Art:

---I--- ---V--- ! ! ! ! V V V V

-------------------------------------- Soil

(5) Measure the voltage you get for some known current and apply a "geometry factor" to get the resistivity.

--
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kensmith@rahul.net   forging knowledge
Reply to
Ken Smith

Whether or not he's on earth. ;-)

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Paul Hovnanian     mailto:Paul@Hovnanian.com
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Bumper sticker: You\'re too close for missiles. Switching to guns.
Reply to
Paul Hovnanian P.E.

Immunity to excessive heating?

Reply to
Ben Bradley

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