Introduction
Knowledge matures when practically gets executed. It gives a person a clear understanding of various things. So, to understand the process of frequency modulation we are here with the interesting project of Simple FM Transmitter by using two transistors. Hence, the circuit works effectively in distant or close ranges.
As you already know that there are different ways to transmit the data. Thus, in frequency modulation, the data is transferred by varying the frequency of carrier waves. Also, there are different ways to make this circuit. Thus, we are making it by using the two transistors FM transmitter. The circuit also requires very few external components which ultimately makes it affordable.
Hardware Components
The following components are required to make FM Transmitter Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Ceramic Capacitor | 10nF, 4.7pF, 100nF | 1 |
| 2. | Resistor | 4.7KΩ, 220KΩ, 22KΩ, 10KΩ, 6.8KΩ, 47Ω | 1 |
| 3. | Transistor | BF494, BC557 | 1 |
| 4. | Battery | 3 to 6V | 1 |
| 5. | Electrolytic Capacitor | 10µF/16V, 4.7µF/16V | 1 |
| 6. | Variable Capacitor (Trimmer) | 3-30 to 5-50pF | 1 |
| 7. | MIC | – | 1 |
| 8. | Inductor | 0.3uH | 1 |
| 9. | Antenna | – | 1 |
BC557 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of BC557
BF494 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of BF494
FM Transmitter Circuit
Working Explanation
To make the Two Transistors FM Transmitterter, we are using the condenser microphone that provides the audio signal. When the audio signal is from the microphone, it converts the signal into an electrical signal and then that signal penetrates at the base of the PNP transistor which increases the amplitude of the signal. The signal gets more amplified by the NPN transistor Q2. To generate the carrier waves, we have created the tank circuit using a capacitor and inductor. Here we are using the variable capacitor which changes the resonant frequency for fine modification. The antenna is connected to send the carrier waves. Now you can hear the audio signal given to this circuit on any of the radios at a close range.
Application and Uses
- It can be used in portable audio devices.
- Also, in-car radios, etc.
