Door Reed Switch Selection

Question

Problem: Door Reed Switch Selection. Solve this hands-on electronics task on EWskills.

Accepted Answer

1. Component Purpose

A reed switch is a magnetically activated switch sealed inside a glass tube. When a magnet comes close enough, the internal reed contacts pull together and close the circuit.

For enclosure door detection, the magnet is mounted on the door and the reed switch on the PCB (or frame). When the door is closed, the magnet is near the switch and the circuit is closed. When the door opens, the magnet moves away and the switch opens.

The controller reads this as a simple digital input: door open or door closed. No mechanical lever, no physical contact with the door — just magnetic proximity.

Required: Glass Body Reed · SPST-NO · 10–20 AT operate range · ≥24VDC · Axial · Through Hole

2. How to Find It on DigiKey

Go to DigiKey.com → Switches → Magnetic, Reed Switches

Apply these filters:

Type → Glass Body
Circuit → SPST-NO
Operate Range → 10 ~ 20 AT
Voltage - Switching DC → 24V or higher
Mounting Type → Through Hole
Termination Style → Axial
Part Status → Active

Tip: AT (Ampere-Turns) is the unit for magnetic sensitivity. A lower AT range means the switch activates with a weaker magnet or at a greater distance. 10–20 AT is a common mid-range sensitivity suitable for door gaps of a few millimeters.

3. Key Specifications & What They Mean

Specification	Required	Why
Type	Glass Body Reed	Standard hermetically sealed reed switch.
Circuit	SPST-NO	Normally open; closes when magnet is near.
Operate Range	10–20 AT	Mid-range sensitivity for door-gap distance.
Switching Voltage	≥24VDC	Must handle 24V sensing circuit.
Termination	Axial, Through Hole	Wire-like leads for PCB or chassis mount.
Temp Range	−40°C to +85°C	Industrial enclosure conditions.

4. Selecting a Safe, Production-Ready Part

The filtered list will show matching parts. Before you pick one, check: Is it Active? Is stock available? Is the manufacturer reputable? Is a datasheet available?

Full checklist: How to Select a Safe, Production-Ready Component — EWskills Guide

5. Filtered DigiKey Link

➡ View Matching Parts — Glass Reed, SPST-NO, 10–20AT, ≥24VDC, Axial

50. Door Reed Switch Selection