Redefining electric current

A team of scientists from the National Physical Laboratory (NPL), Cambridge University and Germany’s National Measurement Institute are collaborating on research that will hopefully lead to redefining electric current with unprecedented accuracy.

Today it is essential that measurements of electric current are precise as possible.

The accuracy of these measurements is essential to a number of diverse industries, including: healthcare, environmental monitoring, telecommunications and power generation.

One of the approaches the scientists are using for the redefinition is an electron pump that transports individual electrons on waves of electrostatic energy.

This can, in theory, generate an electric current of extraordinary accuracy. The scientists are working to explore the pumps in detail, alongside trying out other ways of achieving a redefinition.

One of the other approaches they are testing is exposing an extremely thin wire (100,000 times thinner than a human hair) to microwave energy — this causes the wire’s electrons to vibrate in sync with the microwaves, which results in a precisely controlled flow of electrons through the wire.