2Km Powerful FM Transmitter Circuit

The FM transmitter (Frequency modulation) circuit is made up of a single transistor or a BJT. In wireless communication, the (frequency modulation) FM carries the data or information by changing the frequency of the carrier wave as per the information or a message signal.

The performance and working of the FM transmitter circuit are dependent upon the variable capacitor and inductor. In this article, you are going to learn how you can prepare an FM transmitter circuit and how it works with its various applications.

Things You Must Know About FM Transmitter Circuit:

1) Transmitter

2) Transmission of radio waves

3) Receiver:

Transmitter: The transmitter is an extremely important device, its purpose is to produce radio frequency waves for transmission into space. The important elements of transmitters are as follows:

Microphone:

A microphone is a device that converts sound waves into electrical waves. When the speaker speaks or a musical instrument is played, the varying air pressure generates an audio electrical signal corresponding in frequency to the original signal. The output of the microphone is fed to a multistage amplifier.

Audio Amplifier:

The audio signal from the microphone is quite weak and requires amplification. This job is accomplished by cascaded audio amplifiers. The amplified output from the last audio amplifier is fed to the modulator for rendering the process of modulation.

Oscillator:

The function of an oscillator is to produce a high-frequency signal, called a carrier wave. Usually, a crystal oscillator is used for this purpose. The power level of the carrier wave is raised to a sufficient level by radiofrequency amplifier stages Most broadcasting stations have carrier wave power of several kilowatts. Such high power is necessary for transmitting the signal to the required distances.

Modulator:

The amplified audio signal and carrier waves are fed to the modulator. Here, the audio signal is superimposed on the carrier wave suitably. The resultant waves are called modulated waves or radio waves and the process is called modulation. The process of modulation permits the transmission of the audio signal at the carrier frequency. As the carrier frequency is very high, therefore, the audio signal can be transmitted over large distances. The radio waves from the transmitter are fed to the transmitting antenna or aerial from where these are radiated into space.

Transmission of Radio Waves:

The transmitting antenna radiates the radio waves in space in all directions. These radio waves travel with the velocity of light 3x10 m/sec. Radio waves are electromagnetic waves and possess the same general properties. These are similar to light and heat waves except that they have longer wavelengths. It may be emphasised here that radio waves are sent without employing any wire. It can easily be shown that at high frequency, electrical energy can be radiated into space.

Radio Receiver:

On reaching the receiving antenna, the radio waves induce tiny e.m.f. in it. This small voltage is fed to the radio receiver. Here, the radio waves are first amplified and then the signal is extracted from them by the process of demodulation. The signal is amplified by audio amplifiers and then fed to the speaker for reproduction into sound waves.

Now let's make a FM transmitter:

Now I hope you understood about what is Transmitter, Transmission, radio waves, or receiver. So for making an FM transmitter circuit I am using a custom-made PCB without PCB it's you can make but it creates some little bit of noise. So if you are thinking about making an FM transmitter circuit then I will highly suggest you make this circuit in PCB.

And by the way, I am giving you the GERBER file so you can download and use it for free. For PCB orders you can use JLC PCB You can order your custom made PCB From JLCPCB If you are a new user register on the website throuch our link: https://jlcpcb.com/IYB, and you can get a $30 new user coupon code that you can use in yours first order shipment and SMT service. I would definitely say to use this coupon code.

Click Here 👉 (Gerber)to Download Gerber File.

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Components:

• 2N3904 Transistor
• Condenser MIC
• 4.7K Resistor
• 330 Ohm's Resistor
• 1nf Capacitor (Code 102)
• 22nf Capacitor (Code 223)
• 22pf Capacitor (Code 22) This is the variable capacitor. But here I am using a Fixed value capacitor
• 4.7pf Capacitor (Code 4.7)
• Inductor (Coil, 8turs 6mm dia 0.5mm wire)

Circuit Diagram:

So as I already said The performance and working of the FM transmitter circuit are dependent upon the variable capacitor and inductor. (Coil) so for making a coil or inductor, I will highly suggest you watch my YouTube video In that video I have explained to you the process of making a coil. & Don't forget to turn on CC for a better experience.

Hope the article helped you.

Don't Forget To Watch This Video 😉