Found in an old American documentation this FM modulator makes use of a varactor diode. The circuit can be easily implemented given the small number of components used.
This version of the Pierce oscillator with the 2N3904 was found in the January 1994 issue of...
The traditional configuration of a non-inverting amplifier with the operational 741 shown in the...
This circuit is from a Radio Electronics from January 1958. The transistor is the CK722, and the...