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How does a magnetic door switch work?

Views: 205     Author: China Micro Switch Manufacturer     Publish Time: 2020-08-22      Origin: https://www.unionwells.com/

How does a magnetic door switch work?

Magnetic door switches first came into existence at about the year 1934. They are very similar to relays in the way they operate. They are designed to enable the closing of electrical contacts through the influence of magnetic field. But they are not exactly like relays because they are enveloped inside a glass. 

There are certain benefits that come with using magnetic switches instead of electrical relays. Magnetic switches are entitled to longer lifespan, reduced contact resistance, and the ability to switch between different states much faster. Since they come in sealed forms, you are safe to use them in sensitive environments like places that are prone to explosives and flames. 

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A magnetic switch usually comprises an extended glass capsule that is up to one centimeter long. The diameter is just about a couple millimeters. At least two wires are expected to go through the end of the capsule. Inside the switch, thin and stiff metals are separated from one another with some fractions of a millimeter. These metals usually overlap one another. Let us not forget that the capsule has a hermetic seal that helps it withstand actions like corrosion, as well as any other unfavorable weather activity on the contact of the metals. 

The most basic form of magnetic switches are made up of just two contacts within. But for other more advanced form of magnetic switches, there are multiple metal contacts inside. 


One contact inside the glass capsule will be of a magnetic material while the other will be something non-magnetic. A magnetic field close by will be produced by either a permanent magnet or an electromagnet, resulting to the proximity of the two contacts, enabling the switch to be closed. When the magnetic field is no longer available, the spring in the metal will cause the connection to be broken, thereby leaving the switch open. And because the mass of the contacts is low, they are bound to work much faster than any relay even though they are believed to have similar ratings. 


Since the contacts of a magnetic switch are in close proximity, they are unable to carry large current size. Dealing with currents that is more than some amperes will need a more powerful metal contact. Anything that would function like standard relays would work just fine. There are a handful of magnetic switches that are capable of managing tens of thousands of volts, a lot of them are only designed to work with lower voltages. 

Magnetic closeness

That pulling force produced by the magnet is typical of what is known as the inverse cube law. When the distance to a magnet is doubled, the pulling force of the magnet is reduced to one-eighth of the initial quantity. That implies that a magnetic switch will always be responsive to any nearby magnetic field. For instance, a burglar alarm works with a little permanent magnet that is seated on the door, while the magnetic switch sits close to it atop the frame of the door, and when the door is opened the switch is actuated automatically. 

What is a magnetic switch all about?

In a general term, a magnetic switch can be likened to the simplest light switch. It has a duty to turn a circuit on or off, based on whatever state it is in. but it is quite different from a light switch in that it is operated by a magnet compared to what you have in light switch where you have to control it with your own fingers. So that is about the simplest way one can define a magnetic switch and not get anyone confused in the process. 


Magnetic switches usually come with a metal conductor arm which is fixed to one side, double switch contacts close to the arm that is free, with the inclusion of a movable magnet. Some equally come with double magnetic clamps. 


It will gladden you to know that magnetic switches are of different types. They are actually three in number. Usually, open mono-stable switches stay connected whenever the mobile magnet is near the arm. Usually, closed mono-stable switches stay disconnected whenever the magnetic that is movable is near the arm. Bi-stable switches have the ability to change their positions anytime the magnet moves. Though they maintain in their last state even when the magnet is no longer close to them. 

How they function

Anytime the moving magnet comes to the end of the arm that is free, the metallic arm will be attracted to it. This will bring the end of the arm to meet with the switch contact. Bi-stable switches come with magnetic clamps which maintains the position of the arm even after the magnet is no longer close to them. So that is the working mechanism of the magnetic switch. 

Their user-friendliness in terms of installation and use has made them highly popular among a great number of users. Another reason why they have gained widespread popularity is because they seem to switch much faster than relays. You can use them in just about any type of environment. So you are not limited in how you can apply them. Whether you are using the mono-stable types or the bi-stable units, magnetic switches are highly reliable and the most suitable choice for door detection systems. Regardless of all the various models of magnetic switches that are out there, they all have a single basis of operation. 

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This post have been able to cover magnetic switches in their simplest forms. It has been able to discuss the general definition of these switches to be switches that consists of a magnet as well as a switch that is magnetically sensitive. They are also used in door and window detection systems. You can find them as normally open or normally close types. The world has come to appreciate the use of magnetic switches, and the best way to benefit from this is by investing in it. 

For more about door switches,you can pay a visit to unionwell at https://www.unionwells.com


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