This circuit was obtained from the March 1994 Electronics Now magazine. The circuit uses a common transistor which can be a low noise type such as the BC549.
This project is from the book Science Fair Projects by Newton C. Braga. In it we have a relay that...
This circuit, from a 1975 technical documentation provides a gain of 14 dB at signals from 500 kHz to...
The circuit shown, from an American technical documentation from 1976, is a voltage divider using...