Frequency Modulation (FM) Transmitter


Frequency Modulation (FM) Transmitter


The circuit is a simple but yet a Very High Frequency (VHF)FM Transmitter. This FM transmitter (FM Tx) is about the simplest and most basic FM Transmitter, which is is possible to build and have a useful transmitting range.
It is basically a VHF colipits oscillator capable of transmitting sound or music to any standard FM receiver.The circuit works on a small +9V battery which makes it easily portable. It also has a capacitor microphone which picks up very weak sound signals.
The output frequency can be easily changed. The frequency stability is also quiet good. The range of this transmitter is about 60 to 350 meters which depend upon the size of antenna. It will easily penetrate over three floors of an apartment building and go over 300 meters in the open air. It is surprisingly powerful despite its small component count. It may be tuned anywhere in the FM band. Or it may be tuned outside the commercial M band for the greater privacy.

Frequency Modulation (FM) Transmitter
S. No. component Name Quantity
1 IC CD4069 with 14 Pin Base 1
2 DC Socket M/F 1
3 Berg Strip 2 Pin 2
4 Diode 1N4007 1
5 Capacitor (470uf) 1
6 Capacitor (10uf) 2
7 Capacitor (100pf) 1
8 Capacitor (22pf) 1
9 Capacitor (104pf) 1
10 LED 1
11 On/Off Switch 1
12 BB109 Diode 1
13 Crystal Oscillator (10.7 KHz) 1
14 MIC 1
15 LM7805 voltage regulator IC 1
16 Resistor (1K) 3
17 Resistor (6.8K) 1
18 Resistor (10K) 1
19 Resistor (1M) 1
20 PCB 4×4 inch 1
21 Battery (+9v) with Cap 1


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