Reed Switch, also known as reed switch, reed switch, reed switch or magnetic reed switch, is a magnetic sensitive special switch that is the main component of reed relays and proximity switches.

The reed switch was invented by Walter B. Ellwood of Bell Telephone Laboratories in 1936. He himself applied for a patent in the United States on June 27, 1940, with patent number 2264746.

A reed switch is usually composed of two or more reeds, whose contacts are enclosed in glass tubes filled with inert gases (such as nitrogen, helium, etc.) or vacuum. The ends of the parallel encapsulated reeds in the glass tubes overlap and leave a certain gap or contact with each other to form the normally open, normally closed, or switching contacts of the switch.

The reed switch has a simpler structure, smaller size, higher speed, and longer working life compared to general mechanical switches; Compared with electronic switches, it has strong resistance to load impact and high reliability in operation.

There are two ways to use a reed switch:

1. Permanent magnet

2. Adding an electromagnetic coil (becomes a reed relay)