Use of relay

Replies

• 

  Harshad Italiya

  For which circuit you are asking?
  
  in general meaning you can say that relay is simply working as switch.
  
  according to input of relay it switches its status ON or OFF.
• 

  debu

  @ashutoshglamour: Godfathers answer is exactly correct. The relay is a switch. When activated, it closes a key, like any other switch.
  
  Regards,
  
  Debu 😀
• 

  priyank_180

  it is just Electro-mech switch...
  its choise is depends on your application..
• 

  akkumon

  Linke a switch
• 

  manoj_2all

  Yes it works like a Switch; ON (Active) and OFF (De-active) state but the equipments in remote places.
• 

  sasuke

  Mostly use is for isolated switch. Example separate between low voltage and high voltage. Some application, use in logic controller.
• 

  ivenkii

  That is correct but there are types of relays which will have different operating. Like, Latching relay, Reed relay, Mercury-wetted relay, Polarized relay, Machine tool relay, Contactor relay, Solid-state relay, Solid state contactor relay, Buchholz relay, Forced-guided contacts relay, Overload protection relay.
  
  Here each relay will be operating for different purpose. Most of them seem to be of same kind but if we go in depth we will be knowing abt them...
  Please correct if im wrong.
• 

  sasuke

  Correct. depend on application. Common spec varies are voltage, current, frequency and most spec take in considerable is switching speed. Normally big relay will slowest switching speed and call as contactor.
  
  But now have very fast switching electronic component which call as photocoupler but this type is not a relay type but still function as relay.
• 

  aj_onduty

  The answer is the basic, the definition of the word relay in a dictionary for electrical engineers. If you want to know more, just keep on asking questions. Never mind if you feel that your question is baseless or silly. We are here to correct you.
  Thank you.
• 

  bill190

  A relay is just an electrically operated switch.
  
  A good example of its use is for the starter motor in a car. The starter motor uses a LOT of electricity and needs very large wires to power it. It would be impossible to run those large wires to the key switch in the steering column!
  
  So instead they use a relay at or near the starter motor to switch the large wires, then the relay only needs small wires to switch it on, and these can be run to the key switch. Relays in vehicles are also called solenoids.
  
  So that is one use for a relay, to use a small amount of electricity to switch on a much larger amount of electricity.
  
  In at least the U.S., relays used with building wiring are also called "contactors". I would not be surprised, if around the world, they have other names as well?
  
  Then there is all sorts of thinking which goes into the design of the electrical contacts used in relays. Here is a paper about that...
  #-Link-Snipped-#