NE555 is a very popular IC among electronics hobbyists and students. Because by using this IC they build wide variety of electronic projects like audio projects, LED projects etc. But in this circuit it is used as an audio amplifier. The circuit is very easy to build using few components. Transistor BC 549
BC549 is a general purpose transistor. The required power of the circuit is 9 volt DC. Use a small 8 Ohms speaker with the circuit.