Editing Hall effect sensor (section)

=== Hall switch ===
While the Hall element is an [[analog device]], ''Hall switch'' ICs often additionally incorporate [[Threshold detector|threshold detection]] circuitry to form an [[electronic switch]] which has two states (on and off) that output a binary [[digital signal]].

Their outputs may be [[open collector]] [[NPN transistor|NPN transistors]] (or open drain n-type [[MOSFETs]]) for compatibility with ICs that use different supply voltages.<ref name=":0" /> Rather than a voltage being produced at the Hall sensor signal output wire, an output transistor is turned on, providing a circuit to ground through the signal output wire.

==== Hysteresis ====
[[Schmitt trigger]] filtering may be applied (or integrated into the IC) to provide a clean digital output that is [[Robustness|robust]] against sensor noise. The [[hysteresis]] thresholds for switching (specified as B{{Sub|OP}} and B{{Sub|RP}}) categorize digital Hall ICs as either unipolar switches,<ref>{{Cite web |title=Unipolar Hall-Effect Sensor IC Basics |url=https://www.allegromicro.com/en/insights-and-innovations/technical-documents/hall-effect-sensor-ic-publications/unipolar-hall-effect-sensor-ic-basics |access-date=2023-12-28 |website=www.allegromicro.com}}</ref> omnipolar switches,<ref>{{Cite web |title=Omnipolar Switch Hall-Effect IC Basics {{!}} Allegro MicroSystems |url=https://www.allegromicro.com/en/insights-and-innovations/technical-documents/hall-effect-sensor-ic-publications/omnipolar-switch-hall-effect-ic-basics |access-date=2023-12-28 |website=www.allegromicro.com}}</ref> or bipolar switches,<ref>{{Cite web |title=Bipolar Switch Hall-Effect ICs |url=https://www.allegromicro.com/en/insights-and-innovations/technical-documents/hall-effect-sensor-ic-publications/bipolar-switch-hall-effect-ics |access-date=2023-12-28 |website=www.allegromicro.com}}</ref> which may sometimes be called latches.<ref>{{Cite web |title=AN296067: Hall Effect Switch {{!}} Latching Switch Basics |url=https://www.allegromicro.com/en/insights-and-innovations/technical-documents/hall-effect-sensor-ic-publications/latching-switch-hall-effect-ic-basics |url-status=live |archive-url=https://web.archive.org/web/20230927181352/https://www.allegromicro.com/en/insights-and-innovations/technical-documents/hall-effect-sensor-ic-publications/latching-switch-hall-effect-ic-basics |archive-date=2023-09-27 |access-date=2023-12-28 |website=www.allegromicro.com}}</ref> Unipolar (e.g., A3144)<ref>{{cite web|url=https://www.elecrow.com/download/A3141-2-3-4-Datasheet.pdf|title=A1341, A1342, A3143, and A3144 - Sensitive Hall Effect Switches for High-Temperature Operation|publisher=Allegro MicroSystems|website=www.elecrow.com|archive-url=https://web.archive.org/web/20250322183337/https://www.elecrow.com/download/A3141-2-3-4-Datasheet.pdf|archive-date=22 March 2025|url-status=live}}</ref> refers to having switching thresholds in only one polarity of the magnetic field. Omnipolar switches have two sets of switching thresholds, for both positive and negative polarities, and so operate alternatively with a strong positive or a strong negative magnetic field.

Bipolar switches have a positive B{{Sub|OP}} and a negative B{{Sub|RP}} (and thus require both positive and negative magnetic fields to operate). The difference between B{{Sub|OP}} and B{{Sub|RP}} tends to be greater for bipolar switches described as latches, which remain in one state much longer (i.e. they latch onto their last value) and require a greater field strength to change states than bipolar switches require. The naming distinction between "bipolar" and "latch" may be a little arbitrary, for instance, the datasheet for the [[Honeywell]] SS41F describes it as "bipolar", while another manufacturer describes their SS41F<ref>{{cite web|url=https://www.elecrow.com/download/A3141-2-3-4-Datasheet.pdf|title=SS41F - Hall Latch Position Sensor|publisher=SEC Electronics|website=radiolux.com.ua|date=1 November 2013|archive-url=https://web.archive.org/web/20240602175226/https://radiolux.com.ua/files/pdf/SS41F.pdf|archive-date=2 June 2024|url-status=live}}</ref> with comparable specifications as a "latch".