This circuit with two operating modes was found in the September 1989 issue of Radio Electronics magazine. Other operational amplifiers can be used. The power supply must be dual.
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...