Found in Radio Electronics from the 90s, this siren finds many variations on this site. The transistor must be equipped with a heat radiator.
We find this power oscillator circuit in a 90's Popular Electronics. The circuit can be powered by...
The circuit shown in the figure uses a programmable unijunction transistor (PUT) of the BRY39 type...
With this circuit from the September 1989 issue of Radio Electronics magazine, it is possible to...