PRODYN’s line of precision B-Dot sensors measure the time rate of change in a magnetic field, this includes free field and surface measurements. These differentiating sensors are passive devices that are lightweight and portable. Several models cover frequency ranges from near DC to >10GHz. The “multigap” technology on most models have evenly spaced gaps on the sensing loop circumference. The phasing and position of the gaps produces optimum high frequency characteristics while minimizing E-field response. The surface sensors can also be used to measure surface current density.