Door Buzzer Circuit Diagram (Using IC 555 and LM380N)

How are you all? Hope you are well. By the grace of Allah, I am also well. I am @imranhassan, a student who is interested in learning electronics and loves to teach. Today I am sharing a completely hand-drawn door buzzer circuit diagram using the IC 555 and LM380N IC. I have divided the entire circuit into 4 steps and hand-drawn it so that beginners can easily understand it.

Edited with Canva.

This project creates a simple buzzer system for a door where the alarm sounds when the door is opened or someone comes. It is a simple and effective system which is mainly used for door or intercom systems.

Components used and their functions:

🔹 IC 555 Timer IC (IC1)

Edited with Canva.

Usage: This IC is used to generate timing signals. It acts as the main signal generator of the circuit and controls the game operations.

🔸 LM380N IC (IC2)

Usage: This is an audio amplifier IC. It helps in generating sound output from the speaker and gives strong sound output.

🔹 Resistors (R1, R2, R3, R4, R5)

Usage: These are used to control signal strength and generate timing signals.

🔸 Capacitors (C1, C2)

Usage: Capacitors help in filtering the signal and maintaining the stability of the circuit. C1: 1uF, C2: 100nF.

🔹 Speaker (LS1: 8–40Ω)

Usage: It acts as the main output device of the circuit and produces sound output.

🔸 Diode (D1: 1N3904)

Usage: Used to provide correct direction for the signal path and block unexpected reverse current.

🔹 Switch (SW1: Bell Bush)

Usage: It is used to insert or close the signal in the circuit, which helps to control the start and end of the game or system.

🔸 Battery (9V)

Usage: Provides power to run the circuit.

Step 1: Arrange the IC pinout.

First, I took the paper and took the NE555 Timer IC (IC-01) and LM380N IC (IC-02) and took out its pinouts. NE555 Timer IC (IC-01): This is a popular timer IC which is used to generate signals. The description of its pinouts is as follows:

• Pin 1 (GND): Used as a ground pin.

• Pin 2 (Trigger): This pin is used to start the timer.

• Pin 3 (Output): This pin is used to generate the output signal.

• Pin 4 (Reset): Used as a reset pin, which is connected to VCC.

• Pin 6 (Threshold): Used as a threshold pin.

• Pin 7 (Discharge): This pin is used to discharge the timing capacitor.

• Pin 8 (VCC): Used as a power supply pin.

LM380N IC (IC-02)

This is an audio amplifier IC. Its pinouts are as follows:
Pin 1 (Non-Inverting Input): Used as an input signal pin.

• Pin 2 (Inverting Input): Used as an inverting input pin.

• Pin 3 (V-Out): Used as an output signal pin.

• Pin 7 (Ground): Used as a ground pin.

• Pin 8 (V-Supply): Used as a power supply pin.

Step 2: Pin Connection and Component Connection

Now, I have completed the pin connections of the NE555 timer IC and the LM380N IC.

Pin 1 (Ground Pin) and Pin 2 (Trigger Pin) are connected to each other, through which the ground connection to the ground or negative part of the circuit is ensured.

Pin 8 (VCC) and Pin 4 (Reset Pin) are connected, through which the power supply to the circuit is ensured, and this protects the circuit from automatic reset.

A 100K resistance is connected between Pin 7 and Pin 6, which helps to control the signal strength.

A 100µF capacitor and a 22nF capacitor are added. The capacitor helps to maintain the stability of the circuit and ensures filtering of the output signal.

Step 3: Output Signal and Transistor Connection

Now we will extract the output signal from Pin 3 (Output Pin) of the NE555 IC and process it through the transistor 2N3904. In this step, the output signal is provided from pin 3 and connected to 47 kΩ resistance and 10 kΩ resistances.

Pin 3 (Output Pin): It provides signal output, which is later processed by a transistor and LM380N IC.

47 kΩ resistance: This resistance is used for signal strength control and signal amplification of transistors.

Transistor 2N3904: It is used for signal amplification and control of output devices.

10 kΩ resistance: This resistance is used to filter the signal and support the amplification process.

Step 4: Generate output signal from LM380N IC and connect output device

In this step, the signal is taken from pin 2 (non-inverting input), pin 3 (inverting input), pin 7 (ground), and pin 8 (output) of the LM380N IC and connected to the speaker using various components.

Pin 2 (Non-Inverting Input) and Pin 3 (Inverting Input): These pins are used to connect signals. The LM380N IC processes and amplifies the signal through these pins.

Pin 7 (Ground): This is the ground connection pin, which helps in ensuring the balance of the circuit.

Pin 8 (Output): This provides the signal output from the LM380N IC, which is sent to the next output device, such as a speaker.

This is the fourth step of the connection, where the output signal is being generated from the LM380N IC. Pins 2, 3, 7, and 8 of the LM380N IC are connected. First, the signal is processed through pin 2 and pin 3, which is then output from pin 8. Pin 7 is connected to ground, which helps in maintaining the balance of the circuit. Finally, this output signal is sent to the speaker, where it is converted into sound.

Conclusion

This project helps in making a simple and effective door buzzer circuit, which will act as an alarm system for your door. The circuit is made using the IC 555 and LM380N IC, which ensures proper timing signal generation and sound output. First, the NE555 timer IC acts as a signal generator, and then the LM380N audio amplifier IC amplifies the signal and sends it to the speaker.

This circuit is very effective and simple as a door alarm system. The circuit simply creates a buzzer system and provides a warning by sound output when someone is present at the door or when the door is opened. This is a useful and learning project for new students, which teaches the working of a signal generator, amplification and output sound system.

🟩 Thank you for reading my post and giving your valuable time. Stay well and stay healthy. God bless you. 🟩

Photography Details	📱 Device: Walton Xanon90	📍 Location: Narayanganj, Bangladesh	📷 Captured By: @imranhassan