I cant find a voltmeter that detects minimal voltage to prove the success of a Baghdad battery

I am using copper cylinder, iron rod, cork (to seal and stabilize), and an electrolyte - probably red wine vinegar. I am using a glazed vase to house it.  It all assembles well.  The model I am following, from a youtube video produced .4 volts.  I cannot find a tester that detects such low voltage. Can one be recommended, or, is there another way to demonstrate the voltage? any response to this question or in general would be greatly appreciated.  Helping my son with a science project.  thanks, brad

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I like the voltmeters made by HarborFreight(tm), mostly because they are the cheapest I can find where I live.  Every so often, but not too often, I manage to fry one of my voltmeters, and I would feel bad if that happened to a meter that I paid a lot of money for.

http://www.harborfreight.com/7-function-digital-multimeter-90899.html
http://www.harborfreight.com/7-function-digital-multimeter-92020.html
http://www.harborfreight.com/7-function-multimeter-98025.html

But I didn't reply to this question just to talk about my feelings.
;-)

I'm just saying that I  would expect a cheap voltmeter like to work for the kind of measurement you are writing about, just measuring the no-load voltage on a homemade battery.  

All those meters I linked to are pretty much the same thing, as far as I can tell.  But somehow they're priced differently, from 5 to 10 USD, at the time of this writing.
bradleestoller (author)  Jack A Lopez5 years ago
Thank you so much for responding. I did get a low-cost multimeter from Harbor Freight - which does the trick. Thanks for your generosity.
rickharris5 years ago
Almost any digital multimeter will measure down to milli volts - with the added advantage it has a very high input impedance and so will not affect the observed voltage by loading the circuit.
bradleestoller (author)  rickharris5 years ago
Thank you so much for responding. I did get a low-cost multimeter from Harbor Freight - which does the trick. Thanks for your generosity.
iceng5 years ago
Any multimeter made by Fluke or Simpson or B&K has a Milli volt scale.

A
Simpson 260_.jpgFluke87Meter.jpg
Digital testers at Radio Shack or made by Velleman are nearly as accurate as the expensive Flukes, etc. and can be had for $20 or less.
bradleestoller (author)  Dmclane1015 years ago
thank you so much for that. You are confident that the Velleman sold at Radio Shack can detect outputs as low as .4 volts?
Most meters have a 0.02 V range !!!
bradleestoller (author)  steveastrouk5 years ago
Thank you so much for responding. I did get a low-cost multimeter from Harbor Freight - which does the trick. Thanks for your generosity.
Normally I would say, ask the counter person But these days they don't know
much about what they sell from white or black socks ;-)

Now and then, I get pleasantly surprised by a knowledgeable sales person.

A
bradleestoller (author)  iceng5 years ago
Thank you so much for responding. I did get a low-cost multimeter from Harbor Freight - which does the trick. Thanks for your generosity.
bradleestoller (author)  iceng5 years ago
Thank you so much for responding. I did get a low-cost multimeter from Harbor Freight - which does the trick. Thanks for your generosity.
Dmclane1015 years ago
More simply put; what you are asking for to read your .400 volts from the homemade battery is nothing special. As a previous poster mentioned, any cheap digital tester should do the job. Incidentally, I didn't say Velleman was from radio shack. Look up on Amazon or any electronic store and get a cheap no-name Chinese product. Don't spend more than $30.
bradleestoller (author)  Dmclane1015 years ago
thank you so much for responding. I did get a multimeter from Harbor Freight - which does the trick. Thanks for your generosity.