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NathanAllan
July 31st, 2004, 09:04 PM
Does anyone know where I can find the circuit for a emf detector using a multimeter?? I have tons of parts, and I wanna use some of them. I also have a multimeter. I know there is some kind of probe to be made from bits and pieces, and I have lots of those, too. Any help???


Nathan

Terry Yager
August 1st, 2004, 05:46 AM
Which definition of EMF are you referring to, electro-motive force, or electro-magnetic force (or field)? electro-motive force, IIRC, is just an old obsolete term for voltage, which the multimeter already has the capability to measure. Therefore, I'm assuming you're trying to measure electro-magnetic force, right? Try this one:

http://www.mitedu.freeserve.co.uk/Circuits/Testgear/emmeter.htm

--T

NathanAllan
August 1st, 2004, 05:48 AM
Yes, electromagnetic force. Kinda tired to build anything at the moment but the circuit diagram or plans would be helpful after I get some shut-eye.

hwhall
August 2nd, 2004, 07:52 AM
The disign on that web page says it is limited to only about 100KHz. That is pretty low frequency response. Do have any specific sensitivity frequency requirements? A multimeter can be pressed into RF sensing by putting a 0.01 to 0.001 mFd capacitor across the terminals, connecting one terminal to one end of a germaniun diode (1N34A is a good one) and connecting the other end of the diode to a short length of wire. The wire acts as a pickup and the meter will read like a field strength meter.
--Wayne

NathanAllan
August 2nd, 2004, 01:51 PM
No specific requirements. Just as wide a range as I can get. I had the thing described to me a while back, and I had in mind a kind of coiled antenna setup on a long pole. Guess the person waa thinking about something different. Just free enough to post this, no time as yet to scrounge through parts I have to put this(these) together yet. I was actually thinking of a large rig that canbe mounted on top of a car, but I guess it isn't necessary. I love this stuff.

NathanAllan
August 10th, 2004, 04:01 PM
I'm still here, but my phone lin eat home got cut off cause of a large bill. I should be back up and communicatin' this week though. I was thinking of getting cable and making everything in the house communicate, but whatever. I'll be back online soon. I wanted to drop a note here from the public library computer and let everyone know whom I have been talking to that I didn't disappear, just lost my line for a little while.

Nathan