That is a simple and small two Transistors FM Transmitter. It is right for prepared espionage for the strip from radio Fm or receiver of VHF. Of route, the recreational motive also exists and the kids will adore having a transmitter that lets in talking for a radio FM located at a far off place and like this pretend the undercover agent.

long range fm transmitter

                                         Two Transistors FM Transmitter

Operation of the 2 Transistors FM Transmitter

The voice/track captured through the electret microphone, your voice or close humans’ chats, are mischievous to the base of the PNP transistor Q1 via C1 (10uF) in which is amplified. The resistor R2 collectively with R3 determines this amplification.

After having amplified, the sign is eliminated from the collector of Q1 transistor and mischievous to the base of Q2 transistor (NPN), where it modulates in frequency the signal generated via this level. This level is an oscillator of excessive frequency that operates inside the strip of FM. Your frequency is determined with the aid of L1 (0.3uH) and for the adjustment on the variable capacitor (CV).

The acquired signs and symptoms, already modulated in frequency, they’re mischievous to a related antenna inside the collector of the transistor Q2 (BC557 Transistor).

The range of the transmitter relies upon on this antenna, of the feeding of the circuit and of the location wherein it’s miles running. Inside the open subject, with 6 V battery and an antenna of approximately forty cm of the period, this variety of this Tow Transistors FM Transmitter maybe 1000 meters. With a smaller antenna, the range of this transistor will lessen. A common wall isn’t always an impediment to this transmitter.

Circuit DiagramTwo Transistors FM Transmitter



Q1 – BC557

Q2 – BF494


microphone electret two terminals


 (1/4 W, 5%)

R1–four,7 okayΩ

R2–220 okayΩ

R3–22 okΩ

R4–10 kΩ

R5–6,8 kΩ

R6–47 Ω


C1–10 µF/sixteen V – ELECTROLYTIC

C2–four,7 µF/16 V – ELECTROLYTIC

C3–10 nF – ceramic

C4–four,7 pF – ceramic

C5–a hundred nF – ceramic

CV–trimmer from 3-30 to five-50 pF

Different parts:

L1 – 0.3uH

B1 –three to 9 V

ANT –antenna

Published Circuit Board With full element is given below

 Transistors FM Transmitter published Circuit

 the way to Make FM Transmitter

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