ABSTRACT
Electrostatic fields are present throughout the atmosphere, and there are strong electrostatic fields near high-voltage direct current power lines. The commonly used electrostatic field meters generate an alternating current signal by periodic conductor motion (either rotation or vibration). This alternating current signal is proportional to the electric-field strength, and field-meter calibration is performed in a known electrostatic field. Field mills (also called generating voltmeters) determine electric-field strength by measuring modulated, capacitively induced charges or currents on metal electrodes. Extreme low frequency electric fields in residential and industrial settings are most conveniently measured with free-body field meters, which measure the steady-state current or charge oscillating between two-halves of a conducting body in free space. Ground reference meters are also available for measuring the electric field normal to the ground or some other conducting surface. For electric-field measurements, electrically short dipole antennas with high capacitive input impedance are used with a capacitive load, such as a field-effect transistor.
