The doorbells produce a ringing alert sound so that the resident comes to know that there is somebody at the door. Many homes have two doors for entering. So, sometime it become confusing for the resident to find out on which door visitor is  present. This project on doorbell circuit produces two different sounds and can be used simultaneously on both the doors. This circuit also gives a visual indicator so that deaf person can also know. For this we use different color LED for different door so that it becomes easy to know whether the visitor is present on front door or rear door. This simple circuit is based on transistor, diode, resistor and switches with few more components. Resistor is a two terminal passive component used to control the flow of current into the circuit.

The doorbells produce a ringing alert sound so that the resident comes to know that there is somebody at the door. Many homes have two doors for entering. So, sometime it become confusing for the resident to find out on which door visitor is  present. This project on doorbell circuit produces two different sounds and can be used simultaneously on both the doors. This circuit also gives a visual indicator so that deaf person can also know. For this we use different color LED for different door so that it becomes easy to know whether the visitor is present on front door or rear door. This simple circuit is based on transistor, diode, resistor and switches with few more components. Resistor is a two terminal passive component used to control the flow of current into the circuit.