This receiver of two transistors for the 3.5 MHz band was found in a circuit manual from the 80's. The coil data are found next to the diagram and the transistors can be general purpose PNP.
When the sensor X1 is opened, the relay is energized. When waiting, the current drained is very...
Based on the LF256 operational amplifier, this circuit was found in the September 1989 issue of...
This circuit was found in a 1968’s Motorola documentation. The transistor is from that time. The...