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.
Learn more about Relays
 Solid State Relay Manufacturers 'SSR'
A Solid State Relay consists of semiconductor devices mounted on a printed circuit board ~ encapsulated in plastic.Its main characteristics are resistant to high voltage and high current, contactor-less (no noise), good isolation and ease of heat evaporation.Of course there are no moving part to ware out either.
Integrated Circuit Vendors:
American Zettler, Inc. {General Purpose/Automotive-HVAC-Power-Telcom}
Amperite {Miniature Solid State Relay-Time Delay Relays}
Comus International {Solid State Relay - SSR Module Boards}
COSMO Electronics Corp. {4-pin SIP/Panel Mount Solid State Relay-SSR MOS output relays}
Crouzet {I/O Modules/Mounting Boards}
CRYDOM {Solid State Relays}
Dionics Inc {Power MOSFET Photovoltaic Relay Manufacturer}
International Rectifier {Telcom Relays}
NEC {Solid State Relays}
NTE Electronics Inc. {Solid State Relay Manufacturer}
Phoenix Contact {Rail Mounted Solid State Relay Modules}
Power-IO {Solid state relays, SCR thyristors, solid state contactors, IGBT based relay switching}
Solid State Optronics Inc. {Optically isolated Relays - MOSFET/SCR output}
SSAC Inc. {Time Delay Relay Manufacturer}
Teledyne Relays {Commercial/Military-AC/DC/Bi-Direction Output Solid State Relays}
Mechanical Relay Manufacturers
Mechanical Component Vendors:
Aleph International Corp. {Mercury wetted-high power/voltage-high insulation resistance 'IR'-low thermal EMF, RF relays-SMT relays}
Altech Corp. {Safety Relays}
American Electronic Components Inc. {Large Current Relays}
American Relays Inc. {Reed/High Voltage/Power Relays}
American Zettler, Inc. {General Purpose/Automotive-HVAC-Power-Telcom}
Amperite {PCB Relay; Delay-on dropout, Automotive, Flasher Recycling}
Celduc Group {Reed Relays; SIP and DIP Packages}
Clare {Reed Relays}
Comus International {Dry, Mercury Wetted, High Voltage Reed Relay}
Deltrol Controls {General Purpose-Power-Latching Relays-Buzzer/Clappers}
E. Dold & Sohne KG {PCB Relay; Safety relays, Miniature Relays}
Finder relays Inc. {Power relay - Monitoring relays}
Greenwich Electronics Inc. {Automotive/GP/Heavy Duty/Light Duty/Low Signal Relays}
Guardian Electronic Manufacturing Co. {Mechanical 1 to 30 Amp}
Hamlin {Reed Relays; Miniature reed relay in an SIL package, DIP package}
Hasco Components International Corp. {Reed/Electromechanical Relay Manufacturer}
Leach International Corp. {Military qualified subminiature and half-crystal can relays Commercial/Military}
MEDER electronic {Reed Switches/Relays; General Purpose Reed Relays, SMD Reed Relays, Low Thermal Voltage Relays,
High Insulation, Reed Relays, High Voltage Reed Relays, High Frequency Reed Relays, Reed Relay Module, Latching Reed Relays, Current Loop Reed Relays}
NTE Electronics Inc. {General-PCB-Power-Reed-Time Delay-Magnetic Latching}
Panasonic Electric Works {Power-Signal-PhotoMOS-Automotive Relays}
Phoenix Contact {Rail Mounted Mechanical Relay Modules}
Pickering Electronics {Reed Relay; Instrumentation and Automatic Test Equipment,ATE}
Schneider Electric {Commercial-Military Relay Manufacturer}
Teledyne Relays {Mechanical Relays/TO5/Aerospace/Commercial Industrial}
Tyco Electronics {Switching capabilities: dry circuit to 1,600A, up to 70kV, and as high as 6 GHz. Electromechanical Relay}