Electric current sensor for serial gradiometer for measuring anomalies in earth's magnetic field has superconducting quantum interference switches and superconducting transformer

摘要

The electric current sensor (1) has a number of SQUIDs (Superconducting Quantum Interference Switching Circuits) (4a---4n) with Josephson contacts (5). An input current (E) is fed to the primary coil (L4) of a transformer (2). The secondary coil (L3) is connected to the primary coil (L2) of a second transformer (3). The squids form the secondary of the second transformer and are connected to an output terminal (A) and earth.