This old circuit is suitable for signaling applications. The lamp must be incandescent, and the triac must be mounted on a heat sink. The frequency is adjusted in the 1 M trimpot.
This circuit was taken from the 1974 Ferranti transistor manual. Note the shapes of the signals....
This mini siren, found in a 2003 publication, powers a small piezoelectric transducer, but a...
This fuzz effect is from a 1988 Italian publication, but it can be easily assembled, as the...