Published in Popular Electronics with the curious name of Obnoxious Noisemaker, this 1968 circuit generates random sounds that are reproduced on a loudspeaker. The power transistor can be a BD136.
This short-range FM transceiver uses a headset to listen. We found the circuit in a Japanese...
The CMOS 4046 integrated circuit is seldom used, both due to the difficulty of finding it and the...
We found this circuit in the 1982 Selezione Radio magazine in Italy. The circuit uses an...