In addition to currents traversing a PCB, some magnetic components may also provide external field contributions that must be accounted for to ensure they do not impact, or provide minimal impact to the sensor.

The most common magnetic components observed on PCBs are inductors and transformers. These elements have the potential to radiate to nearby components, although the main component of their fields is typically found in the core material. As these devices are typically powered in a somewhat constant fashion, the easiest way to mitigate their effects is to ensure they are placed at some distance on the PCB from the sensor.

Also consider magnetic relays as a potential source of magnetic emanation, because these devices may also radiate magnetic fields when they are powered on or off, based on their configuration. A straightforward way to circumvent this is to use strategic design options in their place, such as latching relays. These devices, while still magnetic in nature, latch into place and do not hold a magnetic field through current in a coil. The coil quickly engages, and flips a switch internal to the device. This helps to mitigate the potential stray field, because it is only during switching that a magnetic field is produced.

Finally, although obvious, permanent magnets continue to find their way into electronics at an increasing pace. In static applications, such as alignment magnets for true wireless earbud chargers, or the locking mechanism of a case, as well as in more dynamic configurations, such as the rotor-mounted pole magnet used for motor commutation, permanent magnets are being implemented at a greater rate with each new iteration of technology. These devices will also emit constant, in some cases, extremely powerful magnetic fields that must be taken into account when determining the ideal layout for a Hall-effect sensor.