Abstract: An integrated-circuit one-way isolation-coupler for a controlling electrical circuit and a controlled electrical circuit and improvements in carrier-domain magnetometers and other applications thereof. In the isolator a magnetic-field source, such as a flat coil, produces a magnetic field from current applied from the controlling circuit, while a detector such as a carrier-domain-magnetometer detects the magnetic field so produced and produces a signal therefrom. A dielectric medium, such as silicon dioxide or silicon nitride separates the source from the detector. The source, the detector, and the dielectric medium, are all incorporated on a single IC chip, such as silicon, or gallium arsenide, or semiconductor material. An amplifier may also be incorporated and may deliver the amplified signal to the controlled circuit. Preferably there are two carrier-domain-magnetometers located so that they are symmetrical with respect to the flat coil.