Simple FM transmitter circuit


Posted on Feb 6, 2014

A lot of FM transmitter circuits have been already published here. This just another one, a simple two transistor FM transmitter. The first stage of the circuit is a preamplifier stage based on transistor Q1. This is a collector to base biased amplifier stage where resistor R2 sets the collector current and R1 provided the necessary collector to ba


Simple FM transmitter circuit
Click here to download the full size of the above Circuit.

se bias. C1 is the input DC decoupling capacitor which couples the input audio signal to the Q1 base. C8 is the power supply by-pass capacitor. Next stage is the oscillator cum modulator stage built around transistor Q2. Electrolytic capacitor C2 couples the output of the first stage to the second stage. R3 and R4 are the biasing resistors of Q2. R5 is the emitter resistor of Q2. Inductor L1 and trimmer capacitor C5 forms the tank circuit which is necessary for creating oscillations. The modulated FM signal is available at the collector of Q2 and it is coupled to the antenna using capacitor C9.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    120 and 240Vac LED Indicator
    Telephone DTMF decoder Display
    Double oscillator metal detector
    Power Mosfet Inverter
    Frequency-to-voltage converter
    a single transistor smart battery charger
    parallel PIC
    hacking rfid for fun
    Four-Channel Oscilloscope Adaptor
    Test Instruments
    Micro-power 32.768kHz clock oscillator circuit
    MAX1516 charge pump drive circuit diagram
    DK04 monitoring module with the computer communications interface circuits



    Top