A REED SWITCH IS AN ELECTRICAL SWITCH

The term “Reed Switch” can refer to either the small glass electrical component as shown in the above drawing, or a complete assembly that is based around this type, or similar component. On this page, “reed switch” will be used to refer to the component and its functionality. But generally, what is true for a reed switch component is also true for a complete assembly.

A REED SWITCH OPERATES BY A MAGNETIC FIELD

Like any electrical switch, a reed switch is a device used to control the flow of electricity. If a reed switch is open, electricity does not flow; if the switch is closed, electricity flows. But unlike most other types of switches, reed switches do not require someone or something to physically operate them. Reed switches are operated by the proximity of a magnetic field. To change the state of a reed switch from open to closed, or vice versa, a source of magnetic energy merely needs to pass near enough to the switch to cause actuation. The source of magnetic energy, or actuator, is usually just a simple magnet. Because of this, reed switches are often also referred to as magnetic switches, proximity switches or proximity sensors.

A REED SWITCH HAS NO MECHANICAL WEAR

One of the unique characteristics of reed switches is high-speed switching with no mechanical wear. This means long-life and extreme reliability; making them exceptionally cost effective. In addition, reed switches are very versatile, easy to install, compact in size and require no supply voltage for operation.

REED SWITCHES MAY BE ACTUATED THROUGH NON-FERROUS MATERIALS

Reed switches can be actuated through non-ferrous (non-magnetic) materials, such as wood, aluminum, plastic and stainless steel, as long as the magnetic field of the actuator is strong enough to reach the switch through the thickness of the material. This means that a reed switch can be enclosed, or hidden, within a sealed environment and actuated from outside without compromising the switch, protected components or materials inside the enclosure.

REED SWITCHES MAY ALSO BE USED WITH FERROUS METALS

While it is generally not recommended, reed switches can also be used around ferrous (magnetic) materials, such as steel and iron, but special consideration must be given to how the magnetic field of the actuator will be affected by the surrounding materials. Testing for consistent operation and optimal placement of both the reed switch and magnetic actuator, within this type of application, should be conducted to keep from having the magnetic field absorbed or distorted by the presence of ferrous materials.