59040 Series - Firecracker Reed Sensor with Retaining Ribs

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Littelfuse products are not designed for, and shall not be used for, any purpose (including, without limitation, automotive, military, aerospace, medical, life-saving, life-sustaining or nuclear facility applications, devices intended for surgical implant into the body, or any other application in which the failure or lack of desired operation of the product may result in personal injury, death, or property damage) other than those expressly set forth in applicable Littelfuse product documentation. Warranties granted by Littelfuse shall be deemed void for products used for any purpose not expressly set forth in applicable Littelfuse documentation. Littelfuse shall not be liable for any claims or damages arising out of products used in applications not expressly intended by Littelfuse as set forth in applicable Littelfuse documentation. The sale and use of Littelfuse products is subject to Littelfuse Terms and Conditions of Sale, unless otherwise agreed by Littelfuse. "Littelfuse" includes Littelfuse, Inc., and all of its affiliate entities.

The 59040 Press-Fit Firecracker Reed Sensor is a small, cylindrical reed sensor 31.0mm (1.22”) long that presses into a 9.5mm (.375”) diameter hole with a choice of normally open, normally closed or change-over contacts. Capable of switching up to 200Vdc at 10W. Available with a range of sensitivity, cable length, plastic housing color, and connector options. Well suited for position and limit sensing, security, and level sensing applications. Functions best with the 57040 actuator.
Note: The 57040 actuator is sold separately.

  • Magnetically-operated proximity sensor
  • Cylindrical capsule with retaining ribs
  • Operates through non-ferrous materials such as wood, plastic or aluminum
  • Hermetically sealed contacts
  • Customer-defined sensitivity
  • Press-fits into a standard drill size hole of 9.5mm (.375”) diameter
  • Quick and easy press-fit installation that requires no screws, brackets, nor glue.
  • Ribs on capsule compress when inserted into a mounting hole and provide retaining force, allowing simple and secure press-fit installation.
  • Well suited for usage in high-moisture and contaminated environments
  • Non-contact solution, aesthetically more appealing than push-button or lever mechanical-type switches
  • Ideal for battery-powered applications as the contacts do not draw power when in the non-activated state
  • Reed contacts last for millions of operating cycles under micro-controller voltage and current logic-level loads
  • Position and limit switching
  • Security
  • Level sensing
  • Industrial

Access specifications, certifications, check availability and order parts below

Catalog #Switching Power (W)Switching Voltage (V DC)Switching Current (A DC)Switching Voltage (V AC)Switching Current (A AC)Breakdown Voltage (V DC)Max Contact Resistance (Ω)Magnetic Sensitivity (AT)Nominal Activate Distance (mm)Switch TypeMin Operating Temp (°C)Max Operating Temp (°C)Max Operate Time (ms)Max Release Time (ms)StockSamplesCompare
59040-1-S102000.51400.352500.212 to 1825A:SPST-NO-4010511CheckOrder
59040-1-T102000.51400.352500.217 to 2321.2A:SPST-NO-4010511CheckOrder
59040-1-U102000.51400.352500.222 to 2817.9A:SPST-NO-4010511CheckOrder
59040-3-S51750.251200.182000.215 to 2021C: SPDT-CO-4010533CheckOrder
59040-3-T51750.251200.182000.220 to 2518.4C: SPDT-CO-4010533CheckOrder
59040-3-U51750.251200.182000.225 to 3017C: SPDT-CO-4010533CheckOrder
59040-4-S51750.251200.182000.215 to 2021B:SPST-NC-4010533CheckOrder
59040-4-T51750.251200.182000.220 to 2518.4B:SPST-NC-4010533CheckOrder
59040-4-U51750.251200.182000.225 to 3017B:SPST-NC-4010533CheckOrder

pdf icon Sensing Products Selection Guide

This guide provides an introduction to magnetic sensing and options for value-added custom design packages.

pdf icon Flow Sensing in Tankless Water Heaters Application Note

Reed switches and sensors are highly effective solutions for flow sensing applications that can be used for detecting the presence of fluid flow in a system or even measure the rate of fluid flow.

pdf icon Position and Level Sensing in Washing Machines

A most integral appliance in any home is a washing machine. Washing machines have helped made the chore of cleaning clothes quite effortless.

pdf icon Rice Cooker Lid Lock Application Note

The position sensing lid lock ensures that the lid is securely locked in place.

pdf icon Capacitive Loads Application Note

When there is significant capacitance in a reed sensor reed relay or reed switch circuit the peak current and energy switched by the reed contacts should be considered.

pdf icon Inductive Load Arc Suppression Application Note

When a reed switch or reed sensor is used to control an inductive device (relay coil solenoid transformer small motor etc.)

pdf icon Reed Switch and Reed Sensor Activation Application Note

Although a reed switch can be activated by placing it inside an electrical coil many reed switches and reed sensors are used for proximity sensing and are activated by a magnet.

pdf icon Reed Switch Extended Shock Capabilities Application Note

The maximum shock specifications in the Littelfuse catalog are very conservative for most switches smaller than the DRxxxx type. T

pdf icon Vibration Testing and Precautions Application Note

Littelfuse tests sinusoidal vibration according to Mil. Std. 202G Method 204D Test Condition G (10 � 2000 Hz frequency sweep at 30 G or 0.06 inch double amplitude whichever is less).

Part # Part Description RoHS Pb-free RoHS (2015/ 863/EU) Certificate REACH (SVHC’s) Declaration Halogen Free REACH (SVHC’s)
59040-1-U-02-A 59040-1-U-02-A SENS RoHS No 03/11/2018 PbFree No 03/11/2018 CoC_RoHS10_59040-1-U-02-A_12-09-2020 REACH209_Declaration_59040-1-U-02-A_12-09-2020 Yes
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