Using the LM3909 this circuit was found in the January 1992 issue of Radio Electronics magazine. Resistor R1 should be chosen according to the table given next to the diagram.
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...