Active Two-Dimensional Electric Field Imaging at Very Low Frequencies

We present a 2-D electric field imaging array and a new active method to image objects that are not direct sources of electric fields. The array is comprised of D-dot sensor pixels, which measure current proportional to the time derivative of the electric field, and are multiplexed through a lock-in amplifier, which achieves a high signal-to-noise ratio. By placing a large and flat active electrode parallel to the imager, a known voltage and frequency can be applied to create a uniform electric field. Objects placed in the field will then distort the field in shape and strength. The distortions can then be imaged, analyzed, and interpreted. The objects imaged in this research include bodies of dielectrics (e.g., water), wires carrying a dc voltage, and floating wires.