Electronic klaxon BA546
In this project, we're going to make an electronic klaxon that can make many different sounds. Since this klaxon uses the audio power amplifier IC, it can produce a very loud sound.
Take a look at the schematic, and you'll see that the klaxon sound is generated by the astable multivibrator made up of the NAND gate IC1. The pitch of the sound is determined by Ra and Ca.
IC2 acts as an audio power amplifier, and the waveform supplied to this amplifier is set by the values of Rb and Cb.
When you finish wiring up the project, turn power ON, and see what happens when you press S1. You can hear a klaxon sound from the speaker. Try making different tones for the klaxon sound by changing the values of Ra and Ca as well as Rb and Cb.