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FM Transmitter Circuit Type Versatile

This is a design circuit diagram of a versatile FM transmitter. This circuit doesn’t have a coil. The circuit is simple and easy to assemble. This circuit is work based on gate logic concept. This is the figure of the circuit.


The gate N1 acts as a buffer for strengthening the signals from the condenser microphone. The inverter N2 with its associated components forms a radio frequency oscillator in the FM region. The varicaps diode BB109 is used for frequency modulating the audio signal to the carrier wave generated by the oscillator. Inverters N4 t0 N6 are used to drive the antenna. As the N4, N5, N6 are connected in parallel their effective output impedance is very less and can easily drive the antenna. All electrolytic capacitors must be rated 10V.

This circuit is use a 10 cm long wire as antenna. Gates N1 to N6 belong to same IC CD4069. The battery can be a 9V transistor radio battery. Adapters are not recommended because they would induce noise in the circuit.