WE CAN now watch electricity as it flows through even the tiniest circuits. By scanning the magnetic field generated as electric currents flow through objects, physicists have managed to picture the progress of the currents. The technology will allow manufacturers to scan microchips for faults, as well as revealing microscopic defects in anything from aircraft to banknotes.
Gang Xiao and Ben Schrag at Brown University in Providence, Rhode Island, visualise the current by measuring subtle changes in the magnetic field of an object and converting the information into a colour picture showing the density of current at each point
Their sensor is adapted from an existing piece of technology that is used to measure large magnetic fields in computer hard drives. "We redesigned the magnetic sensor to make it capable of measuring very weak changes in magnetic fields," says Xiao.
The resulting device is capable of detecting ...