Reed switches for surface mounting

A magnetically controlled contact (MC) is an electrical circuit element that changes the state of the latter by mechanical closing or opening when exposed to a control magnetic field. A magnetic contact placed in a sealed container is called a sealed magnetically controlled contact, or reed switch.

The principle of operation of the reed switch is quite simple. When the external magnetic field reaches a certain threshold value, the elastic ferromagnetic contacts of the reed switch "stick together" and close the electrical circuit. When the magnetic field is removed due to the elasticity of the contacts, the circuit opens.

The advantages of reed switches are well known. One of them is their durability. Unlike a Hall sensor, reed switches do not require power. Smaller size compared to classic relays designed for the same current. Fast response and high insulation resistance. Isolation of contacts from the influence of the external environment, the absence of mechanical "binding" to the acting element (magnet).

However, the disadvantages of reed switches are also known. This is the "bounce" of contacts caused by their elasticity. And susceptibility to external magnetic fields. And limited speed. And one of the most important drawbacks of reed switches is their fragility, which limits the use of reed switches in conditions of strong vibrations and shock loads.

One way to get around this shortcoming is to use surface mount reed switches. Mounting the reed switch on a printed circuit board increases the rigidity of the structure with the reed switch, thereby reducing fluctuations in the external magnetic field. The board itself with the reed switch can also be considered as a base, which facilitates mounting the reed switch on the surface. In addition, it becomes possible to use automatic lines for the manufacture of devices with reed switches.

The Ryazan plant of ceramic-metal devices produces surface-mounted reed switches both in the classic version ( glass bulb ) and in a plastic case , which creates additional protection for the reed switch's glass case.

Overall dimensions and seats of reed switches

Comparative data of reed switches for surface mounting