The technology used in current sensors is very important, as different sensors may have different characteristics in various applications. Most sensors work because the current carrying wire generates a magnetic field. Current sensing resistors are used to directly measure the current in a circuit. The surface mounted Hall sensor consists of a core, Hall effect device, and signal conditioning circuit. When a current conductor passes through a magnetic core with high permeability to concentrate the magnetic field of the conductor, the sensor will work. The Hall effect device is installed inside the magnetic core at a right angle to the concentrated magnetic field, and is excited by a constant current (in a plane). The energized Hall device is then exposed to a magnetic field from the magnetic core, and the potential difference it generates can be measured and amplified into a process level signal, such as 4-20mA or contact closure.

Inductive sensors use coils through which current carrying wires pass. This will make the current in the coil proportional to the current. This is caused by the magnetic field generated by the flowing current. Inductive sensors are used for alternating current. The sensor has a winding core and a signal conditioner. When a current conductor passes through a magnetic core, it is amplified by the conductor's magnetic field. Due to the alternating current constantly changing the potential from negative to positive (usually at a frequency of 50 to 60 hertz), an expanding and contracting magnetic field is generated, resulting in the generation of current in the winding. The secondary current is converted into voltage and regulated into an output process; Signals such as 4-20mA or contact closure. Magnetoresistance effect - Magnetoresistance effect refers to the property of certain materials whose resistance value changes with the variation of magnetic field. If no magnetic flux is applied, the current flows directly through the electrode plate. If a magnetic flux is applied, the Lorentz force proportional to the magnetic flux density will cause the current path to deviate. When the current path deviates, the distance through the plate increases, resulting in an increase in resistance.