Editing Reed switch (section)

==Uses==
[[File:TXE3Reed Relay.JPG|thumb| A reed relay from a [[TXE|TXE-3]] telephone exchange]]

===Reed relays===
{{Main|Reed relay}}
One or more reed switches inside an electromagnetic coil constitute a reed relay. Reed relays are used when operating currents are relatively low, and offer high operating speed, good performance with very small currents that are not reliably switched by conventional contacts, high reliability and long life.  Millions of reed relays were used in [[telephone exchange]]s in the 1970s and 1980s. In particular, they were used for switching in the British [[TXE]] family of telephone exchanges. The inert atmosphere around the reed contacts ensures that oxidation will not affect the contact resistance.  Mercury-wetted reed relays are sometimes used, especially in high-speed counting circuits.

===Magnetic sensors===
Reed switches actuated by magnets are commonly used in mechanical systems as [[proximity sensor]]s. Examples are door and window sensors in [[Security alarm|burglar alarm]] systems and [[tamperproofing]] methods. Reed switches have been used in laptops to put the laptop into sleep/hibernation mode when the lid is closed. Speed sensors on [[bicycle]] wheels frequently use a reed switch to actuate briefly each time a magnet on the wheel passes the sensor.

At one time [[brushless DC electric motor]]s used reed switches to sense the rotor's position relative to the field poles.<ref name="Collins"/> This allowed switching transistors to act as a commutator, but without the contact problems, wear and electrical noise of a traditional DC commutator. The motor design could also be "inverted", placing permanent magnets onto the rotor and switching the field through the external, fixed coils. This avoided the need for any rubbing contact to provide power to the rotor. Such motors were used in low-power long-service-life items, such as computer cooling fans and disk drives. As cheap [[Hall effect]] [[Hall effect sensor|sensors]] became available, they replaced the reed switches and gave even longer service lifetimes.

Reed switches are used in at least one brand of [[Capsule endoscopy|endoscopic capsule]] to switch on the power source only when the unit is removed from the sterile packaging.

Reed switches may be selected for a particular sensor application when a solid-state device does not meet requirements such as power consumption or electrical interface compatibility.

==== Keyboard switches ====
{{External video|video1=[https://www.youtube.com/watch?v=7qcDrYH7qzs Maxi Switch magnetic reed keyboards with original SA keycaps! (Maxi Switch magnetic reed)]}}
Reed switches were formerly used in the keyboards for computer terminals, where each key had a magnet and a reed switch actuated by depressing the key.<ref>{{Cite web |title=Maxi-Switch |url=https://telcontar.net/KBK/Maxi-Switch/ |access-date=2024-09-18 |website=telcontar.net}}</ref><ref>{{Cite web |title=Електромеханічний завод «Магніт»: ПКМ 1Б ("PKM 1B") |url=https://telcontar.net/KBK/Magnit/#PKM_1B |access-date=2024-09-18 |website=telcontar.net |quote=ПКМ 1Б (“PKM 1B”) is type of fairly low profile reed switch, whose design may have been inspired by RAFI’s keyboard switches (especially as the keycap mount is very similar).}}</ref> Reed switches in  keyboards have largely been superseded by [[Hall effect sensor|Hall effect switches]].<ref>{{Cite web |title=Reed switch vs. Hall effect sensor |url=https://www.yoctopuce.com/EN/article/reed-switch-vs-hall-effect-sensor |access-date=2024-09-18 |website=www.yoctopuce.com}}</ref>

[[File:PKM 1B and Cherry MX switches.jpg|thumb|[[Robik#PKM 1B|PKM 1B]] (left) next to [[Cherry AG#Cherry MX|Cherry MX]]]]

Electric and electronic [[pedal keyboard]]s used by [[pipe organ]] and [[Hammond organ]] players often use reed switches, where the glass enclosure of the contacts protects them from dirt, dust, and other particles. They may also be used to control diving equipment, such as flashlights or cameras, which must be sealed to keep water out under high pressure.