INDUSTRIAL AUTOMATION | Explain working of reed switch. State its advantages.

 Reed Switch: 

Working 

 When two solenoid coils are connected in series addition and when excited/energized the flux produced by both coil is added and it produces operating force on reeds and the contacts are closed. 

 When coils are de-energized contact returns to original position due to spring action of reed itself – no separate spring is required. 

Advantages

 Very low contact resistance, hence negligible voltage drop

 Due to inert gas, no corrosion of contacts 

 Long Life 

 Weight of moving part is negligible hence high operating speed as compare to electromagnetic relays