Schematic Diagram 250mW FM transmitter electronic circuit

Posted on Feb 5, 2014

This FM transmitter electronic project works in FM band and it has a transmission power around 250mW. This FM transmitter electronic circuit is very simple and is based on some common transistors and electronic parts. T1 transistor can be a BC107, BC171 or equivalent, and is used as an small audio preamplifier that amplify the audio signal from t

Schematic Diagram 250mW FM transmitter electronic circuit
Click here to download the full size of the above Circuit.

he microphone. Adjusting the R2 variable resistor, audio signal level from the input ( microphone ) can be adjusted until will be delivered to the T1 preamplifier (an over amplified signal applied to T1 can produce an overmodulation). From T1, signal is delivered to T2 which form an Hartley oscillator (frequency of this oscillator depends of C8, C9 and L1). The transmitter frequency oscillator works in FM band 87. 5-108 MHz and can be set, adjusting C8 capacitor and L1 coil. L1 coil must have four turnings on a 0. 8-1 mm cylinder support with a 6 mm diameter (space between each wire must be around 1 mm ).

Leave Comment

characters left:

Related Circuits

  • New Circuits



    Popular Circuits

    Crystal Radio with LM358N
    Temperature measurement using two cables
    help diagnose stator
    High Voltage Converter: 90V From 1.5V
    Audio Voice-Over Circuit PCB
    ADUC836 1MIPS 8052 MCU + 62kB Flash + Dual 16-Bit ADC + 12-Bit DAC
    Automatic UPS system wiring circuit diagram for Home or Office (New Design With One Live Wire)
    AD9850 DDS Module Motherboard
    Serial PCI Express Bus
    AVR Color Clock
    Pulsed Magnetic Field Therapy (PMFT) Circuit