Logo PTB

Current and Quantum Resistance

Working Group 2.61

Profile

The unit “ampere” for electrical current is the electrical base unit in the International System of Units SI. The working group pursues research, development and optimization of new methods and instruments for traceable and highly accurate measurement and generation of small direct electrical currents in a current range of about 1 fA (10-15 A) to about 1 μA (10-6 A). Of particular importance are methods that are traceable to the electrical quantum effects for resistance - the quantum Hall effect - and voltage - the Josephson effect - with extremely high precision and accuracy. For this, the fact that the electrical current via Ohm's law is related to the electrical quantities resistance and voltage is exploited.

Also, the working group provides maintenance and dissemination of the unit for electrical resistance, the “Ohm”, with direct current via the quantum Hall effect.

Many of the activities of the working group are involved in research projects with international cooperation, for example in the context of the European Metrology Research Programme EMRP (Joint Research Project "Qu-Ampere") and EMPIR (Joint Research Project "e-SI-Amp").

To top

Research/Development

The research and development activities of the working group comprise

This work is performed in close cooperation with the Department 7.2 "Temperature and Synchrotron Radiation" (PTB Berlin).
For the development of novel methods and instruments which enable the measurement and generation of small currents with an accuracy excelling previously available methods by up to a factor 100, the research group was awarded the Helmholtz Prize 2018 in the category "application".

Also, the working group performs

QHE-Sample

basic investigations on the quantum Hall effect with direct current, also in new materials, for the dissemination of the unit "Ohm" for electrical resistance, and for the development of new, user-friendly resistance standards, and

This work is performed in close cooperation with neighbouring departments of Department 2 "Electricity" (PTB Braunschweig).
Many of the activities are involved in research projects with international cooperation, for example within the framework of the European Metrology Research Programme EMRP (Joint Research Project "Qu-Ampere") and EMPIR (Joint Research Project "e-SI-Amp").

To top

Services

The working group provides a calibration service for the calibration of an "Ultrastable Low-Noise Current Amplifier" (ULCA) by means of a cryogenic current comparator.
For further information, please contact the group leader .


Calibration services for measurement instruments and systems for direct electrical currents in the range from 10 fA to 100 A are offered by PTB in working group 2.11 "Direct Current Measuring Techniques" in department 2.1 "Direct Current and Low Frequency".


Further calibration services for higher currents are offered by department 2.3 "Electrical Energy Measuring Techniques".

To top

Information

To top