PRODYN’s AD Model electric field D-Dots are small to medium sized, free-space, high frequency sensors that measure time rate of change of electric displacement. Being differential, they have two asymptotic sensing elements accurately positioned on opposite side of a common ground plate and have a radial output direction. Each has a 100 ohm output that is combined into a single 50 ohm signal using BALUN. This combined signal can then be integrated to give an accurate representation of the field strength (for an example, download this excel spreadsheet). Testing has shown the Prodyn asymptotic design to have less capacitance and high upper frequency characteristics, compared to the AFWL HSD design.

The equation pertinent to this device is:

To gauge the correct sensor for a particular test a calculator is provided to determine the max output from any of the above sensors.  Expected rise time/frequency and expected field strengths should be entered in the relevant boxes click here.