Introduction to the working principle, advantages and disadvantages of magnetic spring switches

A magnetic reed switch, also known as a reed, is an electrical switch operated by an applied magnetic field. It is sealed inside a glass tube by two magnetic springs (usually composed of two metals, iron and nickel). The two magnetic reeds overlap but have a small gap between them. An appropriate external magnetic field will bring the two magnetic reeds into contact. The following article will briefly introduce the working principle and advantages and disadvantages of magnetic spring switches. Let's take a look together!

Operating principle of magnetic spring switch

The working principle of a magnetic reed switch is not as complex as expected. To put it simply, two overlapping and magnetic reeds at the ends are collectively sealed in a glass tube, and the inside of the glass tube is in a vacuum state. At this time, the reed acts as a magnetic flux conductor. When not in operation, the two springs will not contact; When a reed generates a magnetic field through an electromagnetic coil, opposite polarity will be generated outside the magnetic field. When the magnetic force received is greater than the elastic force received by the reed, these two reeds will function, thereby connecting the circuit; When the external magnetic field weakens or even disappears, the reed will rebound due to its original elasticity, which means that the contact surfaces of the two reed plates will separate, and the circuit will open.

Advantages and disadvantages of magnetic spring switches

advantage:

1. The contacts are sealed in a glass tube with inert gas and will not be affected by external atmosphere.

2. The action answers quickly.

3. The motion system and circuitry are located on the same axis, making them suitable for applications with high frequency transmission.

4. Small and lightweight.

5. The contacts have excellent corrosion resistance and wear resistance, long service life, and can achieve stable switching action.

6. Combined with a permanent magnet, it is economical and easy to construct a non-contact switch.

Disadvantages:

1. Magnetic reed switch contacts and reed are relatively small and delicate, and are not suitable for handling reed induced switching caused by large voltages or currents. Magnetic reed switches provide typical voltage and current ratings for switches. It is only necessary to switch high current between the relay circuit of the operating relay coil and the magnetic reed switch.

2. There are many troubleshooting procedures. The faulty reed tube needs to be tested with special instruments (such as AT value tester, insulation and voltage withstand tester, internal resistance tester, etc.).

3. Not suitble for product design with a small error range: The range of AT values is large, and from a cost perspective, it cannot be guaranteed that the AT values of batch products are the same, and the matching magnets are also different.

4. The processing loss of magnetic spring switch is large. The magnetic spring switch is packaged in glass, which can easily be damaged during transportation and processing, affecting the product and service life.

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