Difference between Reed Sensor and Hall Sensor

Reed  sensor and Hall sensor have significant differences in principle, structure, sensitivity, current capability, reliability and application scenarios. ‌

1, Working principle and structure

Reed sensor is an electrical switching device consisting of a pair of movable metal blades called reeds. It works based on the magnetoresistive effect of magnetically sensitive materials. When the external magnetic field is applied, the reed is affected by the magnetic force and closes the circuit. When the magnetic field disappears, the reed recovers and the circuit is disconnected. The reed is surrounded by a thin, fragile glass tube filled with a magnetically sensitive gas (usually nitrogen).

Hall sensor is sensor with hall effect. The hall effect refers to the fact that when a current passes through a conductor, the application of a magnetic field perpendicular to the direction of the current will produce a voltage difference on both sides of the conductor (i.e., Hall voltage). Hall devices use this effect to measure the strength and direction of magnetic fields. The hall device contains a hall plate and a signal processing circuit that converts the hall voltage into an electrical signal related to the magnetic field and outputs.

2, Sensitivity and current capability

Reed sensor: high sensitivity to magnetic field, can detect small magnetic field changes. However, due to its structural characteristics, reed sensor may be affected by external environmental factors as vibration. The current of the reed sensor in the closed state can be large, usually up to a few amps, but too much current may cause the reed to overheat and lose elasticity.

Hall sensor: The sensitivity of hall sensor depends on its design and operating range. High-precision hall devices are able to measure the strength and direction of magnetic fields very precisely. The current of hall devices is generally small, usually in the milliampere class, which gives it greater accuracy and stability when dealing with small current signals.

3, Reliability and application

Reed sensor: Because the reed structure is fragile and easy to be affected by external environment such as vibration, its reliability is relatively low. In addition, reed sensors have voltage and current rating limits, exceeding these values may cause damage. Reed sensors are widely used in automatic test equipment (ATE), motor control, safety systems, measuring equipment, etc. Hall sensor is a solid state device and there is no mechanical moving part inside, so it has high reliability and durability, can work statically in harsh environments and has a long service life.

BST, a manufacturer located in Shenzhen, China, focus on reed sensor and hall sensor. BST has been working in sensor industry for decades and offering all kinds of applications according to customer's need. Please contact BST if there is any question about reed sensor and hall sensor.