Hall Sensor 霍爾傳感器

Hall Sensor 霍爾傳感器

Hall Sensor (霍爾傳感器): 是根據霍爾效應原理開發的感應器。霍爾效應是半導體自由電荷受磁場電流磁力作用而產生，它是由美國物理學家Edwin H. Hall在1879所發現。

Hall Sensor是一種能實現磁電轉換的傳感器，可應用於檢測磁場及其變化與讀取磁帶上的信號。Hall Sensor具有結構牢固、體積小、重量輕、壽命長、安裝方便、功耗小、頻率高、耐震動，不怕灰塵、油污、水氣等汙染或是腐蝕。霍爾元件的工作溫度範圍-55~150度C。

霍爾原件依照功能可分為：

A)霍爾線性元件，其輸出是模擬量。霍爾線性元件的精度高、線性度好；

B)霍爾開關元件，其輸出的是數字量，也就是讀取信號。霍爾開關元件具有無磨損、無觸點、無抖動、無跳回，輸出波行清晰與位置重複精度高(可達μm)等優點。

A Hall effect sensor is a transducer that varies its output voltage in response to changes in magnetic field. Hall sensors are used for proximity switching, positioning, speed detection, and current sensing applications.

In its simplest form, the sensor operates as an analogue transducer, directly returning a voltage. With a known magnetic field, its distance from the Hall plate can be determined. Using groups of sensors, the relative position of the magnet can be deduced.

Electricity carried through a conductor will produce a magnetic field that varies with current, and a Hall sensor can be used to measure the current without interrupting the circuit. Typically, the sensor is integrated with a wound core or permanent magnet that surrounds the conductor to be measured.

Frequently, a Hall sensor is combined with circuitry that allows the device to act in a digital (on/off) mode, and may be called a switch in this configuration.Commonly seen in industrial applications such as the pictured pneumatic cylinder, they are also used in consumer equipment; for example some computer printers use them to detect missing paper and open covers. When high reliability is required, they are used in keyboards.

Hall sensors are commonly used to time the speed of wheels and shafts, such as for internal combustion engine ignition timing or tachometers. They are used in Brushless DC electric motors to detect the position of the permanent magnet. In the pictured wheel carrying two equally spaced magnets, the voltage from the sensor will peak twice for each revolution. This arrangement is commonly used to regulate the speed of disc drives.