In several cases the sound generated is not clearly audible and hence it is required to increase the intensity level so that it can be further used. This circuit based [[wysiwyg_imageupload::]]project demonstrates the principle and operation of a simple sound amplifier. The circuit is divided into three parts: 1.Sensor, 2.Amplifier, and 3. Output.Sensor converts the physical characteristics of sound into electrical pulses, which is amplified by the amplifier unit.The amplified output is obtained across the speaker. This circuit finds applications in security systems and as intermediate circuit to sense/amplify sound signals. The circuit of this project is based on condenser mic which is used as a sensor to sense the audio signals and convert them to electrical pulses. The output of the mic is passed to Transistor T1 through a capacitor C1. Read on more to find out how the circuit is made and how it works.