Despite the mechanical limitations, the reed switch does achieve the designed for goal of zero power consumption since the operation is driven through the introduction of a permanent magnet and the subsequent electromagnetic force which pulls the reeds together.

Hall-effect and TMR sensors both require a bias current through the sensing element which is then influenced through the Lorentz force (Hall-effect) or quantum tunneling (TMR). The TMR sensor is typically higher impedance than the Hall-effect sensor, which results with lower current with the same applied input voltage. As a result, TMR sensors often achieve average operating currents at 1μA or better.

Hall-effect sensors can still compete with TMR in many battery powered applications, however. The typical operating behavior for both sensors is to periodically sample the sensor with the required active bias current. Between samples, the sensor is put into a low-power state for a predetermined period of time. While in this low-power state, the Hall-effect sensor can consume minimal power.

For instance, in the case of TMAG5233 and TMAG5133, these devices are well designed for low-power switching applications such as monitoring interactions with human machine interfaces (HMI). In these cases, data refresh rates can remain very low to reduce the total active time for the sensing element. To minimize average current to the TMAG5233, a sample rate of 5Hz is offered to allow for typical operating currents of approximately 0.55μA. For the TMAG5133, a sample rate of 20Hz is offered to allow for typical operating currents of approximately 1.8μA.

For applications with even more demanding requirements, TMAG5134 consumes hundreds of nanoamps when sampling at 1.25Hz while maintaining high sensitivity due to the integrated flux concentrator.