Introduction

A Doorbell Circuit is a simple electronic system used to alert the occupants of a house or building when a visitor presses a button at the entrance. Doorbells are one of the most common and practical applications of electronics in daily life.

This project demonstrates how a basic doorbell works using simple electronic components.

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Objective of the Project

The objectives of this project are:

• To design a simple and reliable doorbell circuit.
• To understand switch-based triggering.
• To generate an audible alert using a buzzer.
• To learn basic circuit design principles.

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Working Principle

The doorbell circuit operates on a momentary switch mechanism.

Basic Operation

1. When the push button is pressed, the circuit is completed.
2. Current flows through the buzzer or sound-generating circuit.
3. The buzzer produces a ringing sound.
4. Releasing the button breaks the circuit and stops the sound.

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Components Required

Basic Doorbell Circuit

• DC Power Supply (9V–12V Battery)
• Push Button Switch
• Buzzer / Electric Bell
• Resistor (if required)
• Connecting Wires
• Breadboard or PCB

Arduino-Based Doorbell (Optional)

• Arduino Uno
• Push Button
• Buzzer
• Resistor (10kΩ pull-down)
• Jumper wires

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Circuit Diagram

Basic Doorbell Circuit

Battery + ---- Push Button ---- Buzzer ---- Battery -

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Arduino-Based Circuit

Push Button ---- D2 (Arduino)
Buzzer -------- D9
GND ----------- Common Ground

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Arduino Code (Optional)

int buttonPin = 2;
int buzzerPin = 9;

void setup() {
  pinMode(buttonPin, INPUT);
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  if (digitalRead(buttonPin) == HIGH) {
    digitalWrite(buzzerPin, HIGH);
  } else {
    digitalWrite(buzzerPin, LOW);
  }
}

Code Explanation

• Arduino monitors the push button.
• When pressed, the buzzer is activated.
• When released, the buzzer stops.

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Advantages

• Simple and low-cost
• Easy to install
• Reliable operation
• Low power consumption

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Applications

• Residential houses
• Offices and shops
• Schools and institutions
• Security alert systems

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Conclusion

The Doorbell Circuit is a fundamental electronics project that helps beginners understand basic switching and sound generation concepts. It is an essential application used in almost every household and can be upgraded with wireless, smart, or IoT-based features.