We found this circuit in a 1986 documentation. It uses only LEDs, batteries, resistors and the power supply which can consist of 4 batteries or a 9V battery. The basic circuit uses two-color LEDs.
This circuit can be used to detect the signals from the previous circuit or from any radio...
Found in Popular Electronics from the 90's, this circuit makes use of components from the time. |...
This receiver for frequencies up to 18 MHz was found in American documentation from the 1990s. Data...