NU2020-190

INVENTORS
Matthew Grayson*
Chulin Wang
Juncen Li
William Reinhardt

SHORT DESCRIPTION
A novel method for highly accurate low dc voltage measurements using a fully electric switch system to account for thermoelectric offset in measurements

BACKGROUND
Increasingly the development of new electrical technology from characterizing thermoelectric materials or testing delicate electronics for commercial use requires precision low voltage measurements. However, low voltage measurements are subject to undesirable thermoelectric offset voltages in measurements due to junctions that have dissimilar metals that are at different temperatures. In measurement setups such as cryostat or thermostat, multiple junctions with dissimilar metals can exist leading to thermoelectric offset resulting in measurement error that specifically effect low voltage measurements. There exist methods that seek to address this point of measurement error, however, they are laborious and expensive to construct.

ABSTRACT
Northwestern researchers have developed a novel method for thermoelectric voltage offset calibration toward improved accuracy in low dc voltage measurements. Specifically, this technology uses an electrically controlled switching system to alternate between measuring background thermoelectric offset and sample measurement. The difference between these measurements reflects the accurate voltage measurement for the sample. This simple electric calibration method is easy to use, performs competitively against other technology, and is easy to implement with few system modifications allowing for incorporation into most electrical measurement setups.

APPLICATIONS

• Cryostats and Thermostats for measuring:
  • Low-level DC voltage
  • Small temperature difference
  • Temperature-dependent Seebeck measurements for different materials
  • DC Hall voltage

ADVANTAGES

• Easy-to-implement all-electrical calibration method
• Scalably small (chip-level) implementation
• No modification of standard cryostat/thermostat design needed, just an extra wire feedthrough
• Compatible with existing commercial silicon integrated circuit technology

IP STATUS
A provisional application was filed.