We'll now make an electronic organ that can produce a sound over a full octave, using three ICs. The sound is amplified by transistor Q1 so you can hear.
The diagrams might seem a little complex, but try building it anyway - you will find it is not so difficult as you expected. Yes, the electronics are not too difficult as you would have imagined: even the sophisticated computer is the combination of many simple basic circuits.
When you finish wiring up the project, switch power ON and press the keys in turn from S8 to S7, S6.....and the organ plays the scale from do, re, mi, fa, and so on.
Don't press two switches at a time; the organ makes an entirely different sound.