The circuit is from Ferranti's 1974 transistor manual. Transistors are general purpose types, and the output waveform is rectangular. Components can be changed to other frequencies.
Found in an English Maplin documentation from 1983, this circuit generates separate frequency...
This circuit uses a piezoelectric transducer to produce sounds like a buzzer. Frequency is...
Guitar preamp (CB22146E) Found in an English publication from 1989, this circuit uses a still...