What is a Magnetic Reed Switch?
A magnetic reed switch is an electromechanical switch that operates using a magnetic field. They usually come in a two-piece design with one piece containing the magnet and the other piece containing the reed switch. The contacts are usually normally open, closing when a magnetic field is present, although they may be normally closed and open when a magnetic field is applied.
The reed is the metal part inside the switch housing that is relatively thin and wide to make it flexible, and it resembles the reed of a musical instrument.
How Does a Magnetic Reed Switch Work?
A reed switch operates on the principle of magnetism. When a magnetic field is applied to the switch, the ferromagnetic reeds become magnetized and attract each other, closing the circuit and allowing current to flow. When the magnetic field is removed, the reeds demagnetize and return to their original position, opening the circuit and stopping the current flow.
What Are Magnetic Reed Switches Used For?
Security Systems: Detecting the opening of a door and windows. Can be used to trigger an alarm.
Transportation Industry: Speedometers, brake lights and monitoring fluid levels.
Consumer Electronics: Sensing the open/close state of laptops, cellphones and cameras.
Medical Equipment: Infusion pumps, ventilators and blood analyzers.
Pros & Cons
Pros
- No Power Consumption: They can be used in an open or closed state indefinitely without consuming power; they have a long life span and are inexpensive.
- Versatility: They can switch both AC and DC currents and are great in low-power circuits.
- Durability: Their performance isn’t affected by dust or dirt, so they can operate in harsh environments reliably.
- High Sensitivity: They are sensitive to magnetic fields, making them useful in various sensing applications.
Cons
- Limited Miniaturization: Although small, they cannot be miniaturized as much as other surface mount chips.
- Magnet Dependency: They don’t work well if the magnet is more than a few millimeters away.
- Accidental Activation: They can be accidentally activated by other magnetic fields.
E-Switch Magnetic Reed Switch Products
MR1000 Series Detector Switch
The MR1000 Series is a recessed magnetic or reed type switch which comes in a two-piece design. One piece contains the magnet and the other piece contains the reed switch. The MR1000 Series is classified as a detector switch as its intended use is where position detection or sensing is required, such as the opening or closing of a door or removal of an equipment panel. It provides an IP67 rating for dust and moisture protection.
The MR1000 Series is available in two contact gap options: 19.0mm (0.75”) or 25.0mm (1.00”). Both options come with 457.20mm (18” length) #22AWG wire leads to connect to a power source. The switch provides 0.5A, 10VAC or 10VDC contact rating, 150mΩ contact resistance and SPDT N.O. contact arrangement.