Hottest sensor surface view reed and Hall effect s

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Sensor Outlook: reed and Hall effect sensor

in your application, the Hall effect sensor P0.005 is relatively modern, and the reed sensor will still be the best choice

since the introduction of the Hall effect sensor a few years ago, it has captured the designer's design imagination, and it is generally believed that solid-state devices are more reliable than mechanical and electronic devices. However, when comparing reed sensor technology with Hall sensor technology, some noteworthy advantages can be observed

reed sensor technology

the key element in the reed sensor is the reed switch, which was invented by Western Electric Company in 1940. Other main components are open or closed elastic reeds and magnets or electromagnets

after 60 years, the reed switch has been improved to make it more reliable and reduce the cost while improving the quality. Due to these remarkable improvements, reed switches have become the design choice in some demanding applications that require quality, reliability and safety

the most striking application of reed sensor quality and reliability is in automatic test equipment (ATE). The technology is first-class in this kind of equipment. Dry spring switch is used for dry spring relay. It is used in IC, ASIC, silicon wafer test equipment and printed board test equipment as a switch. In these applications, there may be 20000 reed relays in a test system

the failure rate of a relay is set at 50ppm to, so in order to meet this requirement, the quality level of dry spring relay should take the lead in organizing technicians to comprehensively analyze and summarize the theory and practice of quality testing equipment in rubber and plastic, packaging and other light industry industries, which is much better than the requirement of 50ppm. So far, we have never heard of an electromechanical device with such a quality level. Similarly, it is also applicable to some semiconductor devices

once in addition to the quality test of the initial work, the reed relay needs to perform well within its service life. At this point, they have proved to outperform all other switching devices. This is because in many cases, ate works 24 hours a day and 7 days a week, and its cost is the most important. Therefore, the working life of dry spring relay needs millions of times

another example that is beneficial to the reed relay is that it is used as an air sensor. In this system, it has passed the time test in harsh safety applications. Reed sensor is widely used in many automotive safety equipment with high requirements (such as the height of sensitive brake fluid), and is applied in many medical instruments, including cautery equipment, pacemaker and other medical electronic equipment. In these equipment, reed relay isolates small leakage current

comparison between reed sensor and Hall effect sensor due to various physiological reasons

in the technology of reed sensor and Hall effect sensor, its size is shrinking. However, when comparing the reed sensor with the Hall effect sensor (see the attached table), we can see some advantages of the reed:

1. The Hall effect device is generally low price, but it needs to add expensive power supply circuit for power supply, and its output signal is also so low, and it usually needs to add amplification circuit. It can be considered that the final result is that the Hall effect sensor is more expensive than the reed sensor

2. The reed switch has excellent insulation from input to output, and the insulation resistance of the switch is up to 10 Ω. The result is a leakage current of 10 A. It is very important to insert the probe or pacemaker of the human body into the medical electronic equipment, which requires that there should be no leakage current close to the heart. Micro ampere or sub micro ampere current can change the key electrical activity of the heart

3. The dry spring sensor is sealed, so it can work in almost any environment (such as no effect on temperature)

4. The contact of the dry spring switch has a very low on resistance when it is on, with a typical value as low as 50m Ω, while the Hall effect sensor may have hundreds of ohms

5. The dry spring sensor can directly switch the signal range from a few nanovolts to kilovolts, the current from flying ampere to ampere, and the frequency from DC to 6GHz. The output range of Hall effect devices is very limited

6. The magnetic sensitivity provided by the dry spring sensor has a large range, but the support is slightly insufficient

7. The dry spring sensor is insensitive to ESD, and ESD may often damage the Hall effect sensor

8. The reed sensor can withstand high voltage (the minimum rated value is 1000V). Hall effect devices require external circuits with a rated value of 100V

9. The reed sensor can withstand a typical 3-foot drop test, which is similar to the Hall effect sensor

10. Because the reed sensor has no wearing components, the low-level load (lower than 5V and lower at 10mA) can work for millions of times. This is equivalent to the number of semiconductor micro machined devices

11. The reed sensor has no effect on the temperature environment, and the typical working temperature range is from -50 ℃ to +150 ℃, without special additional conditions, restrictions or costs. The operating temperature range of Hall effect sensor is limited

reed products have many good applications. Some reed relay factories are excellent in harsh design and application, and are first-class in quality, reliability and safety


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