DoorBell circuit using UM 66 IC

admin April 27, 2011 29 Comments

Doorbell Circuit


Here is a simple and easy to build doorbell circuit using IC UM 66.The  details of UM 66  is given in the older post Melody Generator using UM 66″. This is a slight modification of that circuit.In the previous circuit you have to keep the switch pressed for making the IC play the full music.Here if once the push button is pressed C1 is charged and the transistor Q2 will keep the IC playing the music till it ends.The time for the IC to play depends on discharging time of C1  which can be set by R1.Set R1 to select your time ,whether full tone or a part in one press.Transistor Q2 drives the speaker.

Doorbell Circuit Diagram with Parts List

Door bell circuit


  • Do not give more than 4.5 V to UM 66.
  • POT R2 is not necessary and can be bye passed .But if included you can set the loudness.

We have many other Tone Generator circuits that you may like take a look:

1. Tone Generator

2. High Power Siren Circuit

3. Melody Generator

4. Doorbell Circuit using 555 Timer

5. UJT Organ Circuit

  • ramanareddy
    September 17, 2013

    all materials and related links are usefull to me

  • tnks very much
    July 28, 2013

    thanks very much for exposing more

  • mushtaq ali khan
    June 17, 2013

    this circuit is not working.the ic configurations are wrong.

  • January 31, 2013

    how can i build this circuit on breadboard?please send reply show build circuit on breadboard or pcb.

  • January 31, 2013

    how can i build this circuit on breadboard? please show circuit on breadboard and on pcb also.

  • sushil
    January 24, 2013

    What does the meaning of 3 on 100k & 10k pot. What value should I place in these two pot.

  • srinivas
    November 2, 2012

    how does R1 vary the time of charging of c1..
    is it directly or inversely proportional

  • December 15, 2011

    I get good help

  • ranjith
    November 4, 2011

    thank u so much for u r valuble information

  • zaid
    October 24, 2011

    i want its complete description
    an any one help me ?????

  • seetharaman
    July 12, 2011

    Hi Kiran see the notes kindly delete R2 and connect speaker to + direct, without pot.

  • ramya
    July 12, 2011

    i saw the circuit it was good but i want to make reverse horn of car.please send me a simple and with loud sound because i am just a beginner of electronic.

    from ramya

  • kiran
    July 12, 2011

    i made the circuit but from the 100k pot fire sparks are coming out.please can you tell me whats wrong in the circuit.

    from kiran

  • keshav bargaje
    April 6, 2011

    i want description about music bell circuit diagram can you send the same on my email id

  • Nirmal vyas
    September 18, 2010

    i want 36 v input operated, 2-3 minit timer musical pcb digram want with parts list. can u send me on my mail id

  • seetharaman
    September 13, 2010

    Hi Maina try for 3481 series ICs HT3820, 4822, AM993-9A etc. any melody generator IC which can work from 2.7 to 5 volt can be used

  • maina
    September 13, 2010

    i cant find um66 in kenya,what equivalent ic would u recomend 4 me

  • seetharaman
    July 10, 2010

    Hi Nishanth you are right Pin no1 common, 2 supply and 3 output.
    This IC is a basic CMOS ROM with built in melody, which is prefixed and cannor be changed.

  • Nishanth
    July 9, 2010

    I need some explanation of the circuit. As far as I know the output of the IC UM66 is from 3rd pin but it is taken from 1st pin. So pls provide some explanation. Pls…

    • mushtaq ali khan
      June 17, 2013


  • omongin ronald eric
    June 6, 2010

    am to get a project for my final year. i need a suggestion of what kind of project i can make am studying a diploma in Telecommunicatiun Engineering can anyone help pliz

  • April 23, 2010


  • Zach
    January 3, 2010

    I can’t find UM66 in Singapore. I’d appreciate your recommendation of an equivalent chip that can simply replace it in the same circuit. Thanks in advance.

  • Anu
    October 6, 2009

    I am building a doorbell for deaf people.A device will be tied to the deaf person’s hands…When the doorbell rings the device should vibrate so that the person knows somone is ringing the bell .Could u tell me a solution for this

  • August 23, 2009

    i feel there must be description over the diagram for better understanding. if it is their i didn’t find.

    July 30, 2009

    door bell

  • vignesh.s
    June 16, 2009

    this circuit has very low sound…!
    \do have any solution

    • admin
      June 16, 2009

      have you adjusted the potentiometer R2??

  • shankara
    November 29, 2008

    Good Info , thanks for sharing..!

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