Reed Relays and
Electronics India Limited
Manufacturer of Reed Switches, Reed Sensors and Reed-based products
Reed Relays and Electronics India Limited Incorporated in 1971
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Actuation Distances for UM-0018-H Reed Switches

Operate and release distances for the UM-0018-H reed switches of cropped, SMD, Horizontal Mount and vertical Mount formations in standard AT bands when actuated (as shown in the sketch) using our standard NdFeB magnets are shown below. All distances given are in mm and standard tolerances of ±0.5mm apply.  Although some of the AT band / magnet combinations will produce similar actuating distances, selecting the right AT band and magnet for an application is important and our AT band FAQ and magnet selection guide will help with this.

Activation Distances for UM-0018-H Cropped Reed Switch

UM-0018-H ultra miniature cropped reed switch dimension
UM-0018-H cropped reed switch dimension
All dimensions are in mm

UM-0018-H (7-12 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
cropped reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.5 – 4.5 3.0 – 5.0
NDR-S 6.0 x 2.5 x 2.5 7.5 – 9.0 8.0  – 9.5
NDR-M  8.0 x 3.0 x 3.0 9.0 – 12.0 10.0 – 12.5
NDR-L 19.0 x 4.0 x 4.0 15.5 – 20.5 17.0 – 21.0
NDC-T Φ2.0 x 4.0 3.5 – 5.5 4.0 – 6.0
NDC-S Φ3.0 x 7.0 8.0 – 10.0  9.0 – 11.0
NDC-M  Φ4.0 x 10 12.0 – 15.5 13.0 – 16.0
NDC-L Φ8.0 x 15.0 23.0 – 30.0 25.0 – 30.5

UM-0018-H (12-17 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Di stance
cropped reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.0 – 3.0  3.0 – 3.5
NDR-S 6.0 x 2.5 x 2.5 5.5 – 7.5 6.0 – 8.0
NDR-M 8.0 x 3.0 x 3.0 8.0 – 9.0 9.0 – 10.5
NDR-L 19.0 x 4.0 x 4.0 13.5 – 15.5 15.0 – 17.0
NDC-T Φ2.0 x 4.0 3.0 – 3.5 3.5 – 4.0
NDC-S Φ3.0 x 7.0 6.5 – 8.0 7.0 – 9.0
NDC-M Φ4.0 x 10 10.5 – 12.0 12.0 – 13.0
NDC-L Φ8.0 x 15.0 20.0 – 23.0 22.0 – 25.0

UM-0018-H (10-15 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
cropped reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.0 – 3.5 3.0 – 4.0
NDR-S 6.0 x 2.5 x 2.5 6.5 – 8.0  7.0 – 9.0
NDR-M 8.0 x 3.0 x 3.0 8.5 – 10.5 10.0 – 11.5
NDR-L 19.0 x 4.0 x 4.0 15.0 – 17.5 16.5 – 20.0
NDC-T Φ2.0 x 4.0 3.0 – 5.0 3.5 – 5.5
NDC-S Φ3.0 x 7.0 7.0 – 9.0 8.0 – 10.0
NDC-M Φ4.0 x 10 11.0 – 13.0 12.0 – 14.0
NDC-L Φ8.0 x 15.0 22.5 – 25.0 24.0 – 27.0

UM-0018-H (15-20 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
cropped reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 1.5 – 3.0 2.0 – 3.5
NDR-S 6.0 x 2.5 x 2.5 5.0 – 6.5 6.0 – 7.0
NDR-M 8.0 x 3.0 x 3.0 7.5 – 8.5  8.0 – 10.0
NDR-L 19.0 x 4.0 x 4.0 13.5 – 15.0 14.5 – 16.5
NDC-T Φ2.0 x 4.0 2.5 – 3.5 3.0 – 4.0
NDC-S Φ3.0 x 7.0 6.0 – 7.0 7.0 – 8.0
NDC-M Φ4.0 x 10 9.5 – 11.0 11.0 – 12.5
NDC-L Φ8.0 x 15.0 20.0 – 22.5 22.0 – 24.0

 

Activation Distances for UM-0018-H SMD Reed Switch

UM-0018-H ultra miniature SMD reed switch dimension
UM-0018-M SMD reed switch dimension
All dimensions are in mm

UM-0018-H (7-12 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
SMD formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 3.0 – 5.0 3.5 – 5.5
NDR-S 6.0 x 2.5 x 2.5 7.5 – 10.5 8.0 – 11.0
NDR-M  8.0 x 3.0 x 3.0 10.0 – 13.5 10.5 – 14.0
NDR-L 19.0 x 4.0 x 4.0 17.5 – 23.5 18.0 – 14.0
NDC-T Φ2.0 x 4.0 3.5 – 6.0 4.0 – 6.5
NDC-S Φ3.0 x 7.0 8.5 – 11.0 9.0 – 12.0
NDC-M  Φ4.0 x 10 13.0 – 17.0 13.5 – 18.0
NDC-L Φ8.0 x 15.0 26.0 – 34.0  27.0 – 35.0

UM-0018-H (12-17 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Di stance
SMD formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.5 – 3.0  3.0 – 3.5
NDR-S 6.0 x 2.5 x 2.5 6.0 – 7.5 7.0 – 8.0
NDR-M 8.0 x 3.0 x 3.0 9.0 – 10.0 10.0 – 10.5
NDR-L 19.0 x 4.0 x 4.0 15.0 – 17.5 17.0 – 18.0
NDC-T Φ2.0 x 4.0 3.0 – 3.5 3.5 – 4.0
NDC-S Φ3.0 x 7.0 7.0 – 8.5 8.0 – 9.0
NDC-M Φ4.0 x 10 11.0 – 13.0 12.5 – 13.5
NDC-L Φ8.0 x 15.0 22.0 – 26.0 25.0 – 27.0

UM-0018-H (10-15 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
SMD formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.5 – 3.5  3.0 – 4.0
NDR-S 6.0 x 2.5 x 2.5 7.0 – 8.0 7.5 – 9.0
NDR-M 8.0 x 3.0 x 3.0 9.0 – 11.0 10.0 – 12.0
NDR-L 19.0 x 4.0 x 4.0 15.5 – 19.0 17.5 – 20.5
NDC-T Φ2.0 x 4.0 3.0 – 4.5  3.5 – 5.0
NDC-S Φ3.0 x 7.0 7.5 – 9.0 8.5 – 10.0
NDC-M Φ4.0 x 10 11.5 – 14.5 13.0 – 15.5
NDC-L Φ8.0 x 15.0 22.5 – 28.5 26.0 – 30.0

UM-0018-H (15-20 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
SMD formed reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.5 – 3.0  3.0 – 3.5
NDR-S 6.0 x 2.5 x 2.5 5.5 – 7.0 6.0 – 7.5
NDR-M 8.0 x 3.0 x 3.0 8.5 – 9.5 9.5 – 10.5
NDR-L 19.0 x 4.0 x 4.0 14.0 – 15.5 16.0 – 17.5
NDC-T Φ2.0 x 4.0 3.0 – 3.5 3.5 – 4.0
NDC-S Φ3.0 x 7.0 6.5 – 7.5 7.5 – 8.5
NDC-M Φ4.0 x 10 11.0 – 11.5 12.0 – 13.0
NDC-L Φ8.0 x 15.0 21.0 – 22.5 23.5 – 26.0

Activation Distances for UM-0018-H Vertical Mount Reed Switch

UM-0018-H ultra miniature vertical mount reed switch dimension
UM-0018-M vertical mount reed switch dimension
All dimensions are in mm

UM-0018-H (7-12 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
Welded reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5  3.0 – 4.5 4.0 – 5.0
NDR-S 6.0 x 2.5 x 2.5 8.0 – 10.5 9.5 – 11.5
NDR-M  8.0 x 3.0 x 3.0 11.0 – 14.0 12.5 – 15.0
NDR-L 19.0 x 4.0 x 4.0 20.0 – 25.0 23.0 – 25.5
NDC-T Φ2.0 x 4.0 4.0 – 5.5 5.0 – 6.5
NDC-S Φ3.0 x 7.0  9.0 – 11.0 10.0 – 12.0
NDC-M  Φ4.0 x 10 15.0 – 18.0 16.5 – 18.5
NDC-L Φ8.0 x 15.0 29.0 – 35.0 31.5 – 36.0

UM-0018-H (12-17 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Di stance
Welded reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5 2.5 – 3.5 3.0 – 4.5
NDR-S 6.0 x 2.5 x 2.5 7.0 – 8.0 9.0 – 9.5
NDR-M 8.0 x 3.0 x 3.0 9.5 – 11.5 10.5 – 13.0
NDR-L 19.0 x 4.0 x 4.0 17.0 – 20.0 19.0 – 23.0
NDC-T Φ2.0 x 4.0 3.0 – 4.0 3.5 – 5.5
NDC-S Φ3.0 x 7.0 8.0 – 9.0 9.0 – 10.5
NDC-M Φ4.0 x 10 12.5 – 15.0 14.5 – 16.5
NDC-L Φ8.0 x 15.0 25.0 – 29.0 27.5 – 31.5

UM-0018-H (10-15 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
Welded reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5  3.0 – 4.0  4.0 – 5.0
NDR-S 6.0 x 2.5 x 2.5 7.0 – 9.5 9.0 – 11.0
NDR-M 8.0 x 3.0 x 3.0 10.0 – 13.0 12.5 – 14.5
NDR-L 19.0 x 4.0 x 4.0 17.0 – 22.0 21.0 – 24.5
NDC-T Φ2.0 x 4.0 3.5 – 5.0 5.0 – 6.0
NDC-S Φ3.0 x 7.0 8.5 – 10.0 10.0 – 11.5
NDC-M Φ4.0 x 10 13.0 – 16.5 16.0 – 18.0
NDC-L Φ8.0 x 15.0 26.0 – 31.5 30.0 – 35.0

UM-0018-H (15-20 AT)

Actuation Sketch Magnet Dimensions Operate Distance Release Distance
Welded reed switch actuation distance
NDR-T 4.0 x 1.5 x 1.5  2.0 – 3.0 3.0 – 4.0
NDR-S 6.0 x 2.5 x 2.5 6.5 – 7.5 8.0 – 9.0
NDR-M 8.0 x 3.0 x 3.0 9.0 – 10.0 10.5 – 13.0
NDR-L 19.0 x 4.0 x 4.0 16.0 – 18.0 19.0 – 21.0
NDC-T Φ2.0 x 4.0 3.0 – 3.5 3.5 – 5.0
NDC-S Φ3.0 x 7.0 7.0 – 8.5  9.0 – 10.0
NDC-M Φ4.0 x 10 12.0 – 13.0 14.0 – 16.0
NDC-L Φ8.0 x 15.0 24.0 – 26.0 27.0 – 30.0