This circuit was found in the RCA Power Transistor manual from the 70's. The circuit uses power transistors of the time.
Found in Popular Electronics from the 1980s, this circuit is intended for switching filters with...
The BA1404 integrated circuit (not very easy to obtain) consists of a complete stereo FM...
This transmitter uses an electret microphone and has a few tens of meters in range. The coil L1 is...