Sensor Configuration
Sensor configurations utilize multiple windings to detect magnetic field gradients rather than absolute values. A differential coil array consists of two or more coils wired in opposition to cancel out common mode interference. This balance is effective only for distant noise sources that affect both coils equally.
Signal Extraction
This arrangement improves the signal to noise ratio by ignoring uniform external fields such as the earth’s magnetism or power line hum. When a target moves past the differential coil array, it creates a localized disturbance that the sensor detects. The resulting output is a voltage proportional to the difference in flux between the individual elements.
This technique is used in non destructive testing to find small cracks or inclusions in metal parts.
Calibration Standard
Balance between the windings is the primary factor in system performance. A differential coil array is measured for its null point, which is the state where the output is zero in a uniform field. Any mismatch in wire length or winding diameter will degrade the common mode rejection.
Technicians use precision bridge circuits to verify that each coil has an identical impedance and inductance.
Environmental Resilience
Enclosures made from non conductive materials protect the wires from mechanical damage. The differential coil array maintains its sensitivity even when exposed to temperature swings or vibrations in industrial settings.
