Radio and Electronics Cookbook

4

A simple electronic organ

Introduction

This project has nothing to do with radio but, let’s admit it, any electronics project is good experience! Why not build this little organ – it will keep the children amused at least! It uses the popular NE555 integrated circuit, which contains a circuit which will periodically switch the voltage on the output pin between the supply voltage and zero. Just how frequently this switching occurs depends upon the components external to the integrated circuit. If this switching occurs several hundred or thousand times a second, the change in voltage produced will generate a musical note when connected to a small loudspeaker. The circuit is shown in Figure 1.

Figure 1 Circuit diagram

Putting it together ...