Daniel Green
University:
Gradation Date: May 2010
Hometown:
My Project: Standardizing Methods for Measuring the High Voltage Output from Electroshock Weapons
This summer I worked in the Detection, Inspection, and Enforcement Technologies program of the Office of Law Enforcement Standards in the Electronics and Electrical Engineering Laboratory at the National Institute of Technology. If you speak acronyms, I worked in the DIET program of OLES in EEEL at NIST. My project this summer was the preliminary work for developing a standardized testing method for evaluating the electrical output of electroshock weapons, like the Taser. Although this law enforcement tool is advertised as “non-lethal,” dozens of people have died after being “Tased.”
As part of my responsibilities, I calibrated and made voltage measurements using a high voltage probe which consisted of an impedance divider network. I also helped assemble and use an electro-optic method to measure the high voltages. This method makes use of the voltage dependence of refractive index for some crystalline materials, like lithium niobate. The applied voltage causes a change in the birefringence and thus in the polarization state of light transmitted through the electro-optic crystal. I learned a lot about polarization of light and a little about optical fibers, diode lasers, and optical detectors.
I also calibrated and made current measurements using a current probe. This consisted of a coil of wire that provided a voltage output proportional to the current carried by a wire passing through the center of the coil. Calibration was performed over a wide range of frequencies since the Taser output is a pulse with a wide frequency content. All data was acquired using a high speed digital oscilloscope and subsequently transferred to a computer for analysis. To analyze and display the data that I acquired, I learned and wrote programs in LabVIEW, a graphical computer programming language.
Despite firing a Taser hundreds of times, I have not managed to shock myself yet.
