This circuit for medium and short wave range was found in an American documentation from 1992. The circuit can use general purpose transistors and the antenna can be external or telescopic.
From an audio signal, this circuit gets two signals of the same amplitude and opposite phases....
This conventional relay light detector circuit uses a 741 as a voltage comparator. The sensitivity...
In this circuit the photo-transistor signal is amplified by a Darlington step and then applied to a...