Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Charge Amplifiers? Electric Field Mill

  1. Sep 22, 2013 #1
    I am currently working on building an electric field mill. I am in the very early stages of building this and I have little experience on the subject, unfortunately. I understand the basics and came up with a formula to calculate the current with respect to time (this is AC current). Unfortunately, the magnitude of my current output will be at most on the order of a nanoamp. This is too small as the ammeter I have is much less sensitive. As I have read in a few papers, a charge amplifier is necessary. I don't know anything about them and have dozens of questions that I can't find answers to. Perhaps even a few key words would help me in the construction of this, but right now I am stuck. What I really want is a simple way to increase the current of my mill by a constant so that I can still use my setup to find the magnitude of electric fields with it. That's the dream at least. Any help would be appreciated, thank you.
  2. jcsd
  3. Sep 22, 2013 #2


    User Avatar
    Gold Member

    Here is a paper that describe the salient features of a charge amplifier in great detail.

    Here is a section from MacGorman, D. R., and W. D. Rust, 1998: The Electrical Nature of Thunderstorms. Oxford University Press,
    http://books.google.com/books?id=_N...onepage&q=field mill charge amplifier&f=false

    Here is a website from a Field Mill DIY project. It includes the schematic with all the parts labeled with part numbers. Notice that the first amplifier he uses is the AD 795.

    (edit: add two more websites of interest)

    Here is a link to a textbook. The chapters shown cover Electrostatic Fields,
    Field Mills, Calibration Fields, ELF and ULF Electric Fields, Natural Horizontal Electric Field at the Earth’s Surface, Free-Body Electric Field Meters, Radio-Frequency and Microwave Techniques, Dipole Antennas, Aperture Antennas,
    Three-Loop Antenna System, Broadband Dipole Antennas

    Here is a website about Electric Field Mills with lots of external links for constructing them: http://a-tech.net/ElectricFieldMill/
    Last edited: Sep 22, 2013
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook