Magnetic Contact Switch Sensor Products

Description

Magnetic contact switches are often used to detect if a door or window is open/closed. It consists of a magnet and reed switch in separate enclosures (ABSAcrylonitrile Butadiene Styrene thermoplastic polymer plastic or metal), where the switch turns on/off when the magnet is near the reed switch. Magnetic contact switches come in three different configurations: Normally Closed (NC), Normally Open (NO), and both Normally Closed or Open (NC/NO). These configuration are defined below.

Normally Closed (NC):: An NC magnetic contact switch is normally closed without the magnet and conducts electricity (i.e., the door opening and removing the magnet would close the switch and allow the current to flow) and the switch opens when the magnet is near it, not allowing current to flow.
Normally Open (NO):: An NO magnetic contact switch is normally open without the magnet and cannot conduct electricity (i.e., the door opening and removing the magnet would open the switch, not allowing current to flow) and the switch closes when the magnet is near it to allow current to flow.
Normally Closed or Open (NC/NO):: These magnetic contact switches have both NC and NO options with three terminals: NC, NO, and COMCommon Ground where COM is the common ground.

There is a common misunderstanding among vendors selling these switches that think the "normal" position is with a magnet next to the reed switch, probably because its in the normal position when on a door/window, so sometimes you see the NC or NO in the title of the product is often backwards. In the product listings below, NC and NO have been corrected to be consistent with the definitions given above, but you may see them reversed on the product page. Before purchasing, it is recommended that you check for any clarification in the product description, product reviews, or Q&A comments.

Magnetic Contact Switches

Normally Closed (NC)

Gebildet Wired Contact Sensor Alarm Magnetic Reed Switch Normally Closed (NC) Black (5PCS)

Seller: Gebildet

Package includes:

5x Reed Switches
5x Magnets
10x Adhesive Stickers
20x Screws

+ About this item:

Sensing distance: 10mm to 15mm
Working current: 0.5A
Working voltage: 100V (1V to 100V)
Maximum power: 10W
This is a Normally Closed (NC) switch. When the magnet is removed, the switch is closed and conductive. When the magnet is near the switch, the switch is open and nonconductive.
Wire length: 33cm
Product size: 29x15.5x9mm

Price: $9.99(Updated UTC)

Amazon.com ()

Normally Open (NO)

JING MC-38 NO Magnetic Contact Switch Sensor (3PCS)

Package includes:

3x Reed Switches
3x Magnets
12x Screws

+ About this item:

Sensing distance: 15mm-25mm
Product size: 64 x 19 x 13mm/2.52 x 0.75 x 0.51 inch.(L*W*H)
Hole Diameter: 4mm/0.16 inch
Max current: 0.5A,
Max voltage: 100V
Maximum power: 10W
Product title and description on Amazon is wrong. This is a Normally Open (NO) switch. When the magnet is removed, the switch is open and nonconductive. When the magnet is near the switch, the switch is closed and conductive.

Price: $8.99(Updated UTC)

Amazon.com ()

uxcell MC-51 Wired NO Magnetic Reed Switch White (5PCS)

Seller: uxcell

Package includes:

3x Reed Switches
3x Magnets
12x Screws

+ About this item:

Sensing distance: 16mm
Product size: 50 x 14 x 12.2mm / 1.97 x 0.55 x 0.48-inch (L*W*H)
Max current: 0.3A,
Max voltage: 200V
Maximum power: 3W
Product title and description on Amazon is wrong. This is a Normally Open (NO) switch. When the magnet is removed, the switch is open and nonconductive. When the magnet is near the switch, the switch is closed and conductive.

Price: Unavailable (Updated UTC)

Amazon.com ()

Augiimor 3Sets MC-32 Wired NO Magnetic Reed Switch White

Package includes:

3x Reed Switches
3x Magnets
12x Screws

+ About this item:

Sensing distance: 15mm - 25mm
Product size: 64 x 13x 13mm/2.52 x 0.51 x 0.51 inch (lL*W*H)
Cable Length: 260mm / 10.24 inch
Hole Diameter: 4mm/0.16 inch
Max current: 0.5A,
Max voltage: 100V
Maximum power: 10W

Price: $7.99(Updated UTC)

Amazon.com ()