当输入量（如电压、电流、温度等）达到规定值时，使被控制的输出电路导通或断开的电器。可分为电气量（如电流、电压、频率、功率等）继电器及非电气量（如温度、压力、速度等）继电器两大类。具有动作快、工作稳定、使用寿命长、体积小等优点。广泛应用于电力保护、自动化、运动、遥控、测量和通信等装置中。seline; white-space: nowrap; position: relative; cursor: pointer;" href="https://baike.so.com/doc/4285976-4489343.html#refff_4285976-4489343-1">[1]
电磁继电器
电磁继电器一般由铁芯、线圈、衔铁、触点簧片等组成的。只要在线圈两端加上一定的电压，线圈中就会流过一定的电流，从而产生电磁效应，衔铁就会在电磁力吸引的作用下克服返回弹簧的拉力吸向铁芯，从而带动衔铁的动触点与静触点（常开触点）吸合。当线圈断电后，电磁的吸力也随之消失，衔铁就会在弹簧的反作用力返回原来的位置，使动触点与原来的静触点（常闭触点）释放。这样吸合、释放，从而达到了在电路中的导通、切断的目的。对于继电器的“常开、常闭”触点，可以这样来区分：继电器线圈未通电时处于断开状态的静触点，称为“常开触点”；处于接通状态的静触点称为“常闭触点”。继电器一般有两股电路，为低压控制电路和高压工作电路。
固态继电器（SSR）
固态继电器是一种两个接线端为输入端，另两个接线端为输出端的四端器件，中间采用隔离器件实现输入输出的电隔离。
固态继电器按负载电源类型可分为交流型和直流型。按开关型式可分为常开型和常闭型。按隔离型式可分为混合型、变压器隔离型和光电隔离型，以光电隔离型为**多。
DRIVECON KVFX-475-E
SCHNEIDER AUTOMATION140-NOA-611-10
FANUC A16B-1211-0062/09B 2 AXIS CONTROL
SIXNET ET-4RTD-4DI2-M ETHERTRAK ET4RTD4DI2M W/ 10baseT
SIEMENS 6ES5-470-4UC11 OUTPUT MODULE ANALOG 8POINT
REPAIRED ALLEN BRADLEY 7300-UOJ1
DRIVECON N2 SERIES VFN2-415-F3
HonEYWELL 60140100-001 PC BOARD BCPUI52B-007, BCPMMU3B-004,BXCP153B-007
HORNER ELECTRIC HE500OCS063M
PACIFIC SCIENTIFIC S22HSNA-RNNM-03
TYLAN FC-280AV MASSFLOW ConTROLLER MODEL FC-280, FC-280-AV
APC 388-2000-002 SERIFLEX SENSORBUS ConTROLLER VME6U-1
NIB SEALED ALLEN BRADLEY S50387-002 REV.02
NIB HACH 47602-00
FANUC A02B-0092-C141OPERATOR'S PANEL W/A16B-1310-0380/04B
HonEYWELL 620-3691
NIB PSYTRonICS P4801
NIB YASKAWA V7-4X VARISPEED DRIVE 460V 3.4A CIMR-V7CU40P74
GE FANUC IC693CPU350-BC CPU MODULE 32K
INDRAMAT 109-0785-4B14-06 PC ConTROL BOARD DSS1.3, 109-0785-4A14-06
SIEMENS 6ES7-133-0HH00-0xB0 DIGITAL I/ORELAY, 8DI/8RO-AC, ET200B-8DI/8RO-AC
WITH 6ES7-193-0CC10-0xA0 TERMINAL BLOCK TB6/AC
CLEVELAND-KIDDERP/N M846-01449-114TYPE UOB-5
CLEVELAND-KIDDERM846-01449-114
CLEVELAND-KIDDERP/N M846-01449-014TYPE UOB-5
NIB BODINE ELECTRIC817 DC MOTOR SPEED ConTROL 115VAC 50/60HZ 0817 GW FPM-0817E
GENERAL ELECTRIC FANUC IC600YB808A INPUTMODULE 10-30V 44B717321-002/2
SET OF STI MS4336
BURTON 513-385-000 FIRING BOARD BRV J, 413-064-000
FUJI ELECTRIC 6KMS243001X4A1 MICRO SAVERII AC DRIVE AF-300MS
METSO AUTOMATION A413240A PIC2 BOARD 26209551 VAT 65425667A
YASKAWA JARCR-XEB01-1 EXPANSION BOARD HE9201012 W/ JARCR-XEB01-2
HARRIS GRAPHICS SE80SS130 PIA/PAMUX INTERFACE ASSEMBLY SE80D129
BARBER COLMAN 441 302.11 PHASE
SCHNEIDER AUTOMATION 140DDO35300 DC OUT 24V 4X8
SIEMENS 6ES7-463-2AA00-0AA0 XMTR MODULEIM463-2, S7400 600M6
DVT 800-4MD55 SERIES800 CAMERA
GE FANUC IC600LX616L16K
THERMO ELECTRON CORP7100B INTERFACE MODEL KRIL-M W/KILLARKGRM-CEN-MOD, GRM-CEN
SCHRADER FLUID POWERA2-MP2-BR-PAP CYLINDER W/ 31501-0110
WITH TWO 74304-8115 COILS 120/60V 110/50V
DANAHER ConTROLS PARTLOW 04622702 POWERSUPPLY BOARD 04622702T, REV. B
POWER ONE BLP55-3000G POWER SUPPLY 1.6A 100-250V 50-60H
VICKERS EEA-PAM-535-A-30 ConTROL AMPLIFIER EEAPAM535A30 KFDG4V-5 ASSY 732-267
SIEMENS U-08B EXPANSION RACK 405-IOEX POWER SUPPLY U-12T , 405-8RLY-I
BANNER ENGINEERING USR2424YP2
BROVIND VIBRATORI NC02N 50-DC CONTROLLER220V, 50HZ
NIB HUB CITY 0220-75460 44 1/1 AB ST
FACTORY SEALED CHROMALOX 3913-20104
FACTORY SEALED CHROMALOX 3913-21144 TEMPERATURE ConTROLLER 391320104
FACTORY SEALED GE FANUC IC600BF904KOUTPUT MODULE 115VAC