We found this circuit in a documentation for radio amateurs from the 70s. The transistors can be the BC548. With it, small speakers of 4 or 8 ohms can be used as microphones.
This vibrato circuit was found in Motorola's 1966 documentation. The circuit uses transistors of the...
The CMOS 4046 integrated circuit is not very common today, consisting of a very efficient PLL for...
We found this circuit in an old publication. The transformer has a 9 or 12 V secondary, and the...