SUPERCONDUCTING QUANTUM INTERFERENCE DEVICE USING SINGLE OPERATIONAL AMPLIFIER MAGNETIC SENSOR

摘要

A magnetic sensor for superconducting quantum interference device using single operational amplifier comprising SQUID, a feedback coil, feedback resistor and an operational amplifier. The voltage signal of SQUID is delivered to one input of the operational amplifier, a bias voltage is delivered to other input of the operational amplifier, and the output of the operational amplifier connects to one end of a feedback resistor, the other end of the feedback resistor connects to a feedback coil that is coupled through mutual inductance with the SQUID so as to generate feedback magnetic flux, the output voltage of the operational amplifier drives the feedback resistance to generate current, thereby forming a flux locking loop. The present invention uses an open loop operational amplifier to implement SQUID magnetic flux locking feedback circuit which simplifies the circuit configuration, decrease the loop delay and thereby achieving higher bandwidth of the flux locking loop.