This operational amplifier circuit with variable gain was obtained in an 80's Electronic Engineering. The circuit applies to other operational amplifiers.
Varicap or varactor is the basic component used in this circuit of an American 80's documentation. The...
This old fashioned amplifier can source some watts to a low impedance loudspeaker. The circuit...
Using a 555 this circuit was found in old documentation, but it is still valid. | Clique na imagem...