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 circuit came out in a publication called Electronics Handbook of 1993. The circuit shows how...
This oscillator can generate signals up to a few megahertz depending on the crystal used. Actually...
The drive levels of this shield are opposite to the previous one. The photo-transistor can be of...