What is "relay"

Relay \Re*lay"\, a. (Mach.) Relating to, or having the characteristics of, an auxiliary apparatus put into action by a feeble force but itself capable of exerting greater force, used to control a comparatively powerful machine or appliance.

Relay \Re*lay"\ (r?-l?"), v. t. [imp. & p. p. Relaid (-l?d); p. pr. & vb. n. Relaying.] [Pref. re- + lay, v.] To lay again; to lay a second time; as, to relay a pavement.

Relay \Re*lay"\ (r?-l?"), n. [F. relais (cf. OF. relais relaxation, discontinuance, It. rilascio release, relief, rilasso relay), fr. OF. relaissier to abandon, release, fr. L. relaxare. See Relax.]

1. A supply of anything arranged beforehand for affording relief from time to time, or at successive stages; provision for successive relief. Specifically:

   1. A supply of horses placced at stations to be in readiness to relieve others, so that a trveler may proceed without delay.

   2. A supply of hunting dogs or horses kept in readiness at certain places to relive the tired dogs or horses, and to continue the pursuit of the game if it comes that way.

   3. A number of men who relieve others in carrying on some work.

2. (Elec.) In various forms of telegraphic apparatus, a magnet which receives the circuit current, and is caused by it to bring into into action the power of a local battery for performing the work of making the record; also, a similar device by which the current in one circuit is made to open or close another circuit in which a current is passing.

   Relay battery (Elec.), the local battery which is brought into use by the action of the relay magnet, or relay.

late 14c., "hounds placed along a line of chase," from Middle French relai "reserve pack of hounds or other animals" (13c.), from Old French relaier "to exchange tired animals for fresh," literally "leave behind," from re- "back" (see re-) + laier "to leave" (see delay (v.)). The etymological sense is "to leave (dogs) behind (in order to take fresh ones)." Of horses, 1650s. Electromagnetic sense first recorded 1860. As a type of foot-race, it is attested from 1898.

c.1400, "to set a pack of (fresh) hounds after a quarry;" also "change horses," from Old French relaiier, from relai (see relay (n.)). Related: Relayed; relaying.

Etymology 1 n. 1 (context hunting now rare English) A new set of hounds. (from 15th c.) 2 (context now chiefly historical English) A new set of horses kept along a specific route so that they can replace animals that are tired. (from 17th c.) 3 (context by extension English) A new set of anything. 4 A series of vehicles travelling in sequence. (from 18th c.) 5 (context athletics English) A track and field discipline where runners take turns in carrying a baton from start to finish. Most common events are 4x100 meter and 4x400 meter competitions. (from 19th c.) 6 (context electronics English) An electrical actuator that allows a relatively small electrical voltage or current to control a larger voltage or current. (from 19th c.) vb. 1 (context obsolete intransitive hunting English) To release a new set of hounds. (15th-17th c.) 2 (context transitive now rare English) To place (people or horses) in relays, such that one can take over form another. (from 18th c.) 3 (context intransitive now rare English) To take on a new relay of horses; to change horses. (from 19th c.) 4 (context transitive English) To pass on or transfer (information). (from 19th c.) Etymology 2

vb. (alternative spelling of re-lay English)

1. v. pass along; "Please relay the news to the villagers"

2. control or operate by relay

1. n. the act of relaying something

2. electrical device such that current flowing through it in one circuit can switch on and off a current in a second circuit [syn: electrical relay]

A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a separate low-power signal, or where several circuits must be controlled by one signal. The first relays were used in long distance telegraph circuits as amplifiers: they repeated the signal coming in from one circuit and re-transmitted it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations.

A type of relay that can handle the high power required to directly control an electric motor or other loads is called a contactor. Solid-state relays control power circuits with no moving parts, instead using a semiconductor device to perform switching. Relays with calibrated operating characteristics and sometimes multiple operating coils are used to protect electrical circuits from overload or faults; in modern electric power systems these functions are performed by digital instruments still called " protective relays".

Magnetic latching relays require one pulse of coil power to move their contacts in one direction, and another, redirected pulse to move them back. Repeated pulses from the same input have no effect. Magnetic latching relays are useful in applications where interrupted power should not be able to transition the contacts.

Magnetic latching relays can have either single or dual coils. On a single coil device, the relay will operate in one direction when power is applied with one polarity, and will reset when the polarity is reversed. On a dual coil device, when polarized voltage is applied to the reset coil the contacts will transition. AC controlled magnetic latch relays have single coils that employ steering diodes to differentiate between operate and reset commands.

A relay is an electronic component; a form of switch.

Relay may also refer to:

upright=1|thumb|Relay's Logo upright=1|thumb|Relay Shop in THSR Zuoying Station, Kaohsuing, Taiwan upright=1|thumb|Relay shop in the Gare d'Arles.

Relay is a chain of newspaper, magazine, book, and convenience stores, mostly based in train stations and airports. It is owned by Lagardère Travel Retail, a subsidiary of Lagardère Group.

Its heaviest concentration is in France, but it also operates in other countries. In 2010, the network had 1,100 shops on 4 continents.

"Relay" (titled "The Relay" in the United States) is a song written by Pete Townshend, the guitarist of The Who, for the band's aborted Lifehouse project. The song was also released as a moderately successful single in 1972. It was also the last non- album single by The Who until " Real Good Looking Boy", thirty-two years later.