Car horn
Electronic

In this project, you are going to blow a car horn by mixing two sounds of different frequencies. After completing the project, you will be able to produces a low-tone horn, simulating one of the various horn sounds.

When you finish wiring, turn power ON and press S1. As far as you hold S1 down, you will be hearing a sound similar to a car horn.

This project has two astable multivibrators configured of transistors. One multivibrator, made up of Q1 and Q2, puts out a tone of approx. 300 Hz.

The other multivibrator, made up of Q3 and Q4, puts out a tone of approx. 500 Hz. The two tones are mixed by Q5, amplified by Q6, and given forth from the speaker. What you hear will be a resonance of two sound sources of 300 Hz and 500 Hz.