The Measurement of Current Transients in a Low Voltage Circuit

Abstract

An oscilloscope with a single-sweep circuit may be used for recording transient currents. If the current changes 1 ampere per microsecond, the oscilloscope shunt may need to have an inductance as low as .02 microhenry. An inductance tenfold lower than this can be obtained easily with a tubular resistor with a coaxial return conductor and coaxial potential leads to the oscilloscope. The resistance is provided by a layer of metal on a glass tube. Pt, Cu, and Ni have been used. Such a shunt was used to record the discharge currents of three condensers. Reasonable agreement between measured and computed currents was obtained.