Senior engineer, General Research Institute for Non-Ferrous Metals, Beijing,
Project consultant, Rimkus Consulting Group, Inc., Houston, TX
Associate professor, Texas A & M University, College Station, TX
(Received 27 November 1995; accepted 29 July 1996)
A digital voltmeter is shown to successfully capture the voltage decay signal during eddy current decay (ECD) measurements at cryogenic temperatures on low-resistivity specimens. The use of a voltmeter simplifies ECD measurements, typically made using a digital oscilloscope. An added benefit of using a voltmeter is that under certain circumstances, measurement precision exceeds that which is normally obtained with a preamplifier-digital oscilloscope combination. Results indicate that the best combination of instruments for capturing extremely weak signals (i.e., those with long exponential time constants) is a preamplifier-voltmeter configuration. Results of a comparative study using a preamplifier-digital oscilloscope configuration, a digital voltmeter alone and a preamplifier-digital voltmeter arrangement are presented and discussed.
Paper ID: JTE11323J