This circuit was found in a Popular Electronics from the 90's. It consists of the solid-state variation of the well-known grid-dip meter. MOSFET is a component not very easy to obtain these days.
This traditional circuit with the 555 was found in a 1984 documentation. In this oscillator, the...
This circuit was obtained in a publication for radio amateurs of 1977. It is used to reduce the...
This LED indicator circuit uses an LM339 comparator. The circuit was found in the January 1995...