This small transmitter appeared in the March 1989 issue of Radio Electronics magazine. The two-transistor circuit used an electret microphone and had a range of a few dozen meters.
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...