9V Loud Speaker Sound Generator Circuit

This article explains a 9V Loud Speaker Sound Generator Circuit that is simple, low-cost, and operates from a 9V DC power supply.

In addition, the circuit gives loud sound compared to simple buzzer, therefore it is useful for alarms, door bells, alerts and projects and also, the circuit uses common transistors, so beginners can build it easily.

Circuit Working:

Parts List:

Components	Values	Quantity
Resistors (All resistors are 1/4 watt)	1k, 4.7k, 2.7k, 68k, 1.2k, 330Ω	1 each
Capacitors	Electrolytic 10uF 25V	2
	Electrolytic 1uF 25V, 33uF 25V	1 each
	Ceramic 0.047uF 50V	1
Semiconductors	Transistors BC337 NPN	2
	Transistor BC557 PNP	1
	Transistor 2N2222 NPN	1
	Red LED	1
	8Ω speaker	1
	9V Power supply	1

First, we apply a 9V power supply to the circuit, and the capacitors begin charging, then this charging process starts the oscillation in Q1, and the signal then passes to Q2 through the coupling capacitor.

Therefore, oscillation becomes stronger and then amplified signal moves to Q3 stage and at the same time LED glows showing operation and next Q3 drives Q4.

Then Q4 acts as a power amplifier and supplies a high current to the speaker, which produces a loud buzzing sound, thus, the entire circuit functions as both a sound oscillator and an amplifier.

How to Build:

To build a 9V Loud Speaker Sound Generator Circuit follow the connection steps:

• First, assemble all the parts as shown in circuit diagram.
• Next, capacitor C1 positive connect to Vcc and negative to GND.
• Then Q1 2N2222 emitter connect to ground, base connect to R2 and cathode of C4 junction and collector connect to R1 and anode of capacitor C2.
• After that, Q2 BC337 emitter connect to ground, base connect to cathode of capacitor C2 and resistor R3 and collector connect to anode of C3 capacitor and capacitor C4 and Vcc.
• Now Q3 BC337 emitter connect to anode of LED and cathode connect to collector of Q2, base connect to resistor R5 one end and R6 resistor and collector connect to base of transistor Q4 through resistor R4.
• Further, Q4 BC557 emitter connect to Vcc, base connect to R4 and collector connect to C5 capacitor one end and one end of speaker and speaker other side connects to ground.

Conclusion:

Overall, this 9V Loud Speaker Sound Generator Circuit is simple and it uses easily available parts which produces strong sound output; therefore it is suitable for alarms and alerts.

Moreover, beginners can understand transistor working and also this circuit is reliable and easy to build.