Hall effect sensors

Makes a Square wave

The operation of a Hall sensor is based on the Hall Effect:

A constant electric current flows through a thin, rectangular piece of semiconductor material (the Hall element).

When a magnetic field is applied perpendicular to the direction of this current, it exerts a force on the charge carriers (electrons), pushing them to one side of the material.

This accumulation of charge creates a voltage difference across the sides of the sensor, called the Hall voltage (V_H).

Crucially, the magnitude of the V_H is directly proportional to the strength of the magnetic field. The sensor's circuitry then converts this voltage into a useful electrical signal, often a simple "on/off" digital signal (a switch) or a continuously varying analog signal.

Because they are activated by a magnetic field, they are non-contact, which means they don't wear out like mechanical switches.

Hall sensors are used extensively in vehicles because they are durable, precise, and reliable in harsh environments. Their main job is to measure position, speed, and rotation.

Crankshaft/Camshaft Position Sensors

Works with a magnetized timing ring or rotor to send precise timing signals to the engine control unit (ECU). This is essential for determining when to inject fuel and fire the spark plugs.

Wheel Speed Sensors

Used as part of the Anti-lock Braking System (ABS) and Traction Control System (TCS). They detect the rotational speed of each wheel (often by sensing teeth on a wheel-bearing ring) to prevent skidding.

Throttle Position Sensor (TPS)

Monitors the position/angle of the throttle pedal/valve to tell the ECU how much air and fuel the engine should get

Gear Position/Shifter Sensors

Detects the position of the gear selector eg park, reverse, drive in automatic transmission

Current Sensors

In electric and hybrid vehicles, they are used to monitor the current flow in high-voltage battery systems and motor control for efficient power management and safety (without making physical contact with the high-current wires).