What is a reed switch and why do you need one in your business?

Some devices are not widely known, but their absence can cause big problems with security controls. One of them is the reed switch. A small sensor that can trigger an alarm, send a notification to your phone, or stop a production line when it detects irregularities. At ITH, we know very well that even the smallest component is of great importance for the proper operation of the entire system. For years we have been designing and implementing low-current installations, alarms, intelligent building systems and electrical networks, which almost always include magnetic detectors.

What exactly is a magnetic reed switch?

This is a magnetic sensor that responds to the presence of a magnetic field. Each model has its own parameters, such as the maximum switchable voltage of the reed switch or the contact opening distance, which determine how quickly and under what conditions the sensor will respond. Inside it are contacts that are normally open or closed, and under the influence of an approaching magnet their state changes. This is enough to send a signal to a control panel, a smart home system or a device in a manufacturing plant. Thanks to this simple mechanism, reed sensors are reliable and used wherever fast response is important.

What are the types of reed sensors?

Reed switches can be divided into two types – it all depends on how they are to work and where they will be installed.

• NO (normally open) – at rest (without the presence of a magnet) the circuit is broken. Only when the magnet is approached, the contacts close, i.e. the circuit is closed. Such detectors can be used for specific applications, where the signal is to be generated when the element is closed (e.g. door, flap).

  NC (normally closed) – without the presence of a magnetic field, the contacts are closed (the circuit is closed). Under the influence of an approaching magnet, the contacts open (the circuit is broken). When the magnet is moved away, the contacts close again. Such a reed switch is most often used in alarm systems for monitoring doors and windows.

Magnetic detectors: wired or wireless?

There is no single correct answer. Wired reed switches are stable, so we often use them in larger installations (office buildings, businesses and industrial facilities). Their installation requires advance wiring planning, but thus does not force battery power.

Wireless reed switches are easier to install, especially when modifying an existing installation, so they will be suitable for single-family homes. They can be linked to an app on your phone, and can even trigger a light when the door is opened.

Recessed or surface mount?

At ITH, we care not only about the technical aspects of the system, but also about convenience, which is why we offer different types of reed switch mounting – usually recessed or surface mounted.

• Recessed reed switches retract into the door or window frame, making them virtually invisible.

• Surface ones are visible, but quick to install and easy to replace if necessary.

The choice of solution always depends on the specific project, so we always tailor the scope of activities to the needs of our clients.

Where are magnetic reed switches used?

Alarm systems – a reed switch will notify you if someone opens a window or door when no one should be home.

Smart Home systems – you can get a notification on your phone that your child has come home or that someone has left a window open.

Industrial automation – reed switches control the position of equipment, production safety and the condition of machinery.

Access control – doors, gates, server cabinets.

How to check if it works?

Do you need a security system that won’t let you down?

The ITH team will help you plan, select and install reed switches in such a way that you can have peace of mind whether it’s an office, warehouse or production line. Call or write and we will provide you with the details of cooperation.

FAQ – Frequently Asked Questions

What is a reed sensor?

A reed sensor is a small device used in alarm systems and building automation, among other applications. It reacts to the presence of a magnet, detecting the opening of a window or door, for example.

What is the maximum switching current and switching voltage of the reed switch?

The maximum switchable current usually ranges from 0.2 A to 0.5 A, and the maximum switchable voltage – from 20 V to 50 V (depending on the model). Always refer to the technical specifications for details.

What is the closing distance of the reed switch contacts?

The closing distance of the reed switch contacts depends on the specific model and type of magnet, but in most standard reed switch sensors it is in the range of 10-30 mm. This means that the contacts close when the magnet comes within this distance from the reed switch.

Which type of mounting to choose – recessed or surface?

Recessed mounting is discreet – the sensor is hidden in the window frame or doorframe. Surface mounting is faster and does not require drilling holes.

What are the parametric resistors in reed switches used for?

Parametric resistors built into the sensor facilitate cooperation with the control panel – they allow, for example, to detect sabotage or cable cut.

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