How to build 4W FM Transmitter

December 11, 2010 - category: FM transmitter


  • Stabilised tendency of catering: Vcc=12~16V
  • Frequency of emission: 88~108MHz
  • Consumption: 100~400mA

Circuit diagram:

4W FM Transmitter-Circuit diagram


  • The resistors are 1/4W.
  • R1, R2 10KOhm
  • R3 47Ohm
  • C1, C2 1nF
  • C3 4,7uF/16V
  • C4, C7, C8 0~45pF trimmer
  • C5, C6 10pF
  • C9 100nF
  • L1 4 turns, 7mm diameter *
  • L3 3 turns, 7mm diameter *
  • L4 5 turns, 7mm diameter *
  • L2 RFC (resistance 1MOhm with wrapped around her inductor of enough coils from fine isolated wire. Scratch of utmost inductor and you stick in utmost the resistance making thus a parallel L-r circuit.)
  • T1, T2 2N2219
  • ANT Simple dipole l/2.
  • MIC IN Microphone dynamic or other type. (It can also connected to a cassette player unit)
  • * The inductors is air from wire of coaxial 75W or other 1mm roughly.


Before you print it out with microsoft paints, set the screen resolution to 1280 by 1024 in order to get the correct scale

4W FM Transmitter-PCB


  • With the C4 we regulate the frequency.
  • With their C7, C8 we adapt the resistance of aerial (practically to them we regulate so that it is heard our voice in the radio as long as you become cleaner).


The T2 wants refrigerator.

author: Kyriakos Kontakos, kkontak@hotmail.com
circuit from http://www.electronics-lab.com/

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