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Measuring String Resistance with a Frequency-Varying Input Signal
August 11, 2011

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Innovators at NASA's Johnson Space Center (JSC) have patented a method for measuring individual string resistance within a multiple string component. It is necessary to evaluate string health in order to monitor the condition of component systems such as batteries, thermistors, and sensors that output resistances. This innovation requires only two measurements of a perturbation: voltage and resistance. The system involves connecting one or more frequency-varying impedance components with known electrical characteristics to each string and applying a frequency-varying input signal to the string network. The technology not only allows identification of string resistance but also identifies actual location of any particular string in the network. JSC has received patent number 7,212,934 for this technology.


  • Variable: Facilitates analysis of many circuits; analysis can be tailored for specific behavior
  • Straightforward: Resolves parallel or series resistances without shunts or extra voltage monitoring
  • Fast: Offers simultaneous measurement of resistance networks
  • Robust: Features design flexibility via a series circuit modifications
  • Efficient: Offers convenience over conventional battery testing methods


  • Battery systems
  • Fuel gauging systems
  • Hybrid electric vehicles
  • Systems with multiple sensors and limited processing capability
  • Data acquisition systems
  • Neural network sensor feedback


Johnson Space Center has received patent protection (U.S. 7,212,934→) for this technology.

Licensing and Partnering Opportunity

This technology is being made available through JSC's Technology Transfer and Commercialization Office, which seeks to transfer technology into and out of NASA to benefit the space program and U.S. industry. NASA invites companies to consider licensing this technology for commercial applications.

Contact Information

If you would like more information about this technology or about NASA's technology transfer program, please contact:

Technology Transfer and Commercialization Office
NASA's Johnson Space Center
Phone: 281-483-3809
E-mail: jsc-techtran@mail.nasa.gov

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Page Last Updated: January 16th, 2014
Page Editor: NASA Administrator