Technical

Measuring Reed Switches

Most switches are opened or closed by a physical force that either rocks, slides or rotates electrical contacts together or apart. A reed switch is a clever device that opens and closes electrical contacts without being physically touched, relying on the invisible force of a magnetic field. Inside a simple reed switch are two small metallic reeds with a gap between them. As a magnetic field is moved close to the reeds a positive magnetic force develops in one of the reeds, and a negative magnetic force develops in the other. Since these opposite forces attract, the reeds bend towards each other and make an electrical connection. If the magnetic field is removed, the two reeds are no longer attracted and relax back to their normal disconnected positions.

Reed Switch Precautions

How to handle reed switches, how to modify, cut or form reed switch terminals or leads.

Reed Switches Used with Permanent Magnets

How reed switches behave in a magnetic field emanating from a permanent magnet. How different magnet and reed switch orientations are used in proximity sensors.

Reed Switch Ampere Turns (AT) vs. Milli-Tesla

Ampere turns is a common way to measure reed switch sensitivity. Milli-Tesla is an alternate measure.

Reed Switch as a Proximity Sensor

Reed switches close and open when interacting with a magnetic field. Understand how this interaction can be structured to create motion sensors, proximity sensors, pressure sensors, fluid level sensors, rotation sensors and a host of other applications.

Reed Switch used in a Relay

Inductive coils can be used to introduce a magnetic field to actuate a reed switch. Understand how a coil and a reed switch combine to create relays for a multitude of applications.