We found this circuit in a Linear Technology documentation from the 80's. It has a demodulator, being suitable for links and remote controls. Note the unusual type of detector configuration.
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...