Here is the circuit diagram of a magnetic proximity switch that finds a lot of applications in many fields.The circuit is based on a magnetic reed switch(S1) as the proximity sensor. A monostable multivibrator based on NE555 (IC1) and a toggle flip flop based on CD4013 (IC2) does the rest of the circuit.

When a magnet is reached in proximity of S1 it closes to give a negative trigger at pin 2 of IC1.The output of IC1 goes high for a time determines by R2 and C2.This clocks the IC2 wired as a toggle flip flop.The output (pin 1 ) of IC2 goes high and the transistor Q1 is biased to ON.The relay is activated and so do the equipment connected to the relay.The LED D1 glows when IC1 is triggered.

Circuit diagram with Parts list.



  • Switch S1 can be a general purpose magnetic reed switch.
  • The equipment to control can be connected using NC,NO and C points of the relay according to the application.
  • Use a 12 regulated power supply for powering the circuit.


  1. sachdeva joginder

    looking for circuit diagram for photoelectric proximity sensors please tell us if you can supply

  2. sachdeva JOGINDER

    we are in the line of masking sensors we want diffrent type of circuits with your back upo support pl advice us how we can go ahead with the same

  3. in IC2 pin 16 does what and is it pin 16 or pin?

  4. german hernandez

    muchas gracias por haberme permitido pertenecer a esta pagina prestigiosa

  5. could i get a simple diagram of the reed switch??

  6. am making a magnet activated lock using this circuit so i will like to know more about its sensitivity.