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  • #31
    Overhauser mag. re: Willy

    Thank you, Willy !
    It is difficult for constructing a overhauser magnetometer, isn't ?
    I havn't any reference except some articles down load from net.
    I want to know:
    1) the material of free radical and it ingredient;
    2) the concentration of liquid;
    3) the freqency of polariting and its power.

    Hubert Dong

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    • #32
      Re: Overhauser mag. re: Willy

      You could buy the 4-OXO TEMPO product at http://www.sigmaaldrich.com under the product nr 179485-1G. It costs around 40$ per gram but with that quantity you can make half a liter of solution at .01 mole/liter, which is enough for a BIG sensor.

      For a solution of 0.01 mole / liter you need 0.01 mole for 1 liter. So 0.01 mole X 171.24 grams/ mole for this product = 1.7124 grams.

      For the frequency, I do not know exactly but it must be a few tens of MHz and its power is very small.

      With this principle, the required constant polarization current is much lower than with a standard PPM.

      Willy

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      • #33
        just start on project

        hi sir
        my final year project is magnetometer,
        can you help me from the basics and afterwards
        with due regards
        sajjad
        [email protected]
        [email protected]
        Originally posted by Tod



        Hi all.


        Well, I was able to find a LM2904 in my junk circuit board inventory. It seems to have about the same spec as the LM358, at least it goes to ground. I put it together just as you said Carl, and it worked fine. Then I integrated it into the AD605 variable gain amp and with a little trouble, I got that to work. Analog”s applications bulletin on the AD605 uses caps for AC coupling on VGN and Vin, I removed them and it seemed to work better. Now that I have all that, I’m not sure where to put it, and GREG, I don’t need an answer from you If looking at the schematic gives any one an idea on where to incorporate this ramp let me know. I can send a high res copy to any one that wants it, just email me and I’ll send it right out. Even the high res is not all that good because it was faxed to me from Raytheon and there copy is about 4 generations old.


        Thanks,


        Tod


        [email protected]

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