Found in an old American documentation this FM modulator makes use of a varactor diode. The circuit can be easily implemented given the small number of components used.
This ultra-simple 9 V power source was obtained in an Argentine publication of the 1970s, but it...
We found this filter in the 1990 Motorola Linear Databook, but it can be implemented with other...
The AC125 transistor is an ancient germanium type widely used in audio stages as a preamplifier. In the...