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Relay is also another name for a Repeater and a series of medium-altitude satellites; the first of which was launched in 1962. "Relay" can also refer to relay races. A relay is an electrical switch that opens and closes under control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835. Because a relay is able to control an output circuit of higher power than the input circuit, it can be considered, in a broad sense, to be a form of electrical amplifier.

These contacts can be either Normally Open (NO), Normally Closed (NC), or change-over contacts.

  • Normally-open contacts connect the circuit when the relay is activated; the circuit is disconnected when the relay is inactive. It is also called Form A contact or "make" contact. Form A contact is ideal for applications that require to switch a high-current power source from a remote device.
  • Normally-closed contacts disconnect the circuit when the relay is activated; the circuit is connected when the relay is inactive. It is also called Form B contact or "break" contact. Form B contact is ideal for applications that require the circuit to remain closed until the relay is activated.
  • Change-over contacts control two circuits: one normally-open contact and one normally-closed contact with a common terminal. It is also called Form C contact.

Operation


When a current flows through the coil, the resulting magnetic field attracts an armature that is mechanically linked to a moving contact. The movement either makes or breaks a connection with a fixed contact. When the current to the coil is switched off, the armature is returned by a force that is half as strong as the magnetic force to its relaxed position. Usually this is a spring, but gravity is also used commonly in industrial motor starters. Relays are manufactured to operate quickly. In a low voltage application, this is to reduce noise. In a high voltage or high current application, this is to reduce arcing.

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American men set 4x100 freestyle relay world record http://bit.ly/67unQQ
staronline (The Star) Thu, 24 Dec 2009 03:52:10 -0000
American men set 4x100 freestyle relay world record http://bit.ly/67unQQ
American men set 4x100 freestyle relay world record: MANCHESTER, England (AP): Michael Phelps helped the United.. http://bit.ly/6DhED6
SportMalaysia (SportMalaysia® ) Thu, 24 Dec 2009 03:51:23 -0000
American men set 4x100 freestyle relay world record: MANCHESTER, England (AP): Michael Phelps helped the United.. http://bit.ly/6DhED6
PHOTO FEATURE: 10th day of GJNM Relay Hunger Strike in New Delhi: http://wp.me/p8x2G-a6M
barunroy (barunroy) Thu, 24 Dec 2009 03:50:23 -0000
PHOTO FEATURE: 10th day of GJNM Relay Hunger Strike in New Delhi: http://wp.me/p8x2G-a6M
American men set 4x100 freestyle relay world record http://bit.ly/6DhED6
thestarsports (thestarsports) Thu, 24 Dec 2009 03:46:58 -0000
American men set 4x100 freestyle relay world record http://bit.ly/6DhED6
@ninacreque my mac is dead :/ clifford relay my message about the flights?
iammusic86 (iammusic86) Thu, 24 Dec 2009 03:37:58 -0000
@ninacreque my mac is dead :/ clifford relay my message about the flights?
Route set for Monday's torch relay http://bit.ly/8jmPIN
ConcertsUnlimit (Silas Pradetto) Thu, 24 Dec 2009 03:33:57 -0000
Route set for Monday's torch relay http://bit.ly/8jmPIN

 
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Blossoms Network - Offers clearinghouse network for the exchange of orders between member florists in the United States and Canada. Includes membership application and list of services.
Meta Description: [ Blossoms Network Floral Services wire services for florists ]

FloralSource Inc. (FSI) - Offers a clearinghouse for web-based transfer of fresh floral arrangement orders between member florists in the United States and Canada. Includes marketing information and membership application.
Meta Description: [ Florist Direct Billing Services: Florist Network of the Future ]

Florist2Florist (F2F) - Provides flat fee relay network for the exchange of florists' orders in the UK. Details programs and software.

FTD, Inc. - Offers the clearinghouse transfer of floral and gift orders between affiliated flower shop members and from consumers to those members. Includes membership services and wholesale catalog of products.

Independent Florist's Association (IFA) - Florist-owned association offering clearinghouse and marketing support for the exchange of orders between members in the United States and Canada. Includes member benefits and international order information.

MyTeleflora.com - Offers order exchange clearinghouse for the transfer of fresh floral arrangements and related products to local florist members for fulfillment. Includes member services and wholesale product catalog.

Petals - Provides web-based network for the exchange of orders between florists and from consumers to florists both nationally and internationally. Offices in Australia and The Netherlands.

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