Doorbell Circuit Diagram with Parts List 

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.

 

• 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.