Found in a documentation from the 90's, this circuit already includes an amplification stage. The 12 V power supply allows its use in the car.
We found this circuit in an article in Electronics Now magazine from November 1997. The circuit uses...
This circuit provides just over ½ W to a small speaker. We found this configuration in an old...
In the figure we have a typical relaxation oscillator with a SIDAC as well as waveforms and...