Normally closed reed switch is an electronic switching device, usually used to detect the presence of a magnetic field or to trigger the switching of a circuit, although the normally closed reed switch itself is normally closed, but will be a magnet with its use can realize some specific applications and functions, the following is a detailed description.

I. Magnetic field detection

Normally closed reed switches can be used to detect the presence of a magnetic field. When a magnetic field of sufficient strength is close to the reed switch in the vicinity, the magnet attracts the metal piece in the reed switch and causes it to close, thus triggering the circuit. This configuration is commonly used in applications such as security switches and door magnetic alarm systems to monitor the opening and closing status of doors and windows or the position of other objects.

II. Circuit Triggering

Magnets can be used to trigger a normally closed reed switch to open or close a circuit. For example, a normally closed reed switch is mounted on a door and then a magnet is mounted near the door frame. When the door is closed, the magnet approaches the reed switch, closing it and opening a circuit associated with a security system or lighting control. When the door is open, the magnet leaves the reed switch and the circuit closes.

Ceramic Ferrite Cylindrical Magnets with picture

III. Security and Control

Normally closed reed switches with magnets can be used for security control and automation applications, they can be used to ensure the status of equipment or doors and windows, or they can be used to trigger the operation of alarms or automated systems.

The above is a description of why a normally closed reed switch needs a magnet, the combination of a magnet and a normally closed reed switch can be used for a variety of applications including detection, control, security and automation, the presence of a magnet allows the reed switch to change state when a magnetic field is induced to achieve the desired function.

Content highly relevant articles;

Relationship between reed switch and magnets