Found in an April 1977 Radio Electronics issue, this circuit uses the well-known XR2206. The C1 values for the various frequency bands are given next to the diagram.
This small FM transmitter for clandestine listening has a good range and should be powered by a 9...
This circuit has a high input impedance and provides a good signal at its output. The power must...
This traditional metronome configuration uses unusual transistors in the original version, but it...