Creating a Simple Buzzer Circuit

In this guide, we will create a simple yet effective electronic buzzer circuit, costing less than £5 and powered by just a 9-volt battery.

This circuit is straightforward to build and offers excellent functionality, without the risk of electrical leakage or electric shock from mains voltage (220V). Additionally, an LED will illuminate to indicate the circuit is operating correctly.

The circuit utilises two matched transistors (CS 9012 and CS 9013), which work in conjunction with a few resistors and capacitors to form an oscillator circuit that generates a sound signal frequency. The resistors (R = 1.2kΩ) and capacitor (C = 0.047µF) determine the output frequency, which can be slightly adjusted by modifying these components. However, based on experimentation, this particular configuration yields the most optimal frequency.