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.
What differentiates this circuit from the many versions with the 4017, presented in our...
This is another possible version of a negative voltage generator using a 555 integrated circuit. The...
This circuit was found in Maxim's documentation from the 90's. The circuit provides 12 V x 120 mA....