This circuit was found in documentation from the 1970s. The transistor supports modern equivalents. L1 with C4 determines the frequency range of the signals that will be produced.
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...