This is an intriguing DIY project of FM Radio transmitter. The circuit produces and transmits 27 MHz electromagnetic waves or signals conveying messages. It transmits sound data in the form of electromagnetic signals.
These radio transmitters are frequently utilized in vehicles. Yet may likewise using in fixed locations or areas. For example, communicating or broadcasting sound signals from a PC sound-card in buildings. Moreover, most transmitters normally have a short range of 100–300 feet (30–100 meters). It is contingent upon the quality of the receiver, and other factors like obstructions and elevations.
Furthermore, this circuit creates a very low RF power on the 27 MHz bands. But, the yield power is sufficiently enough for hearing, in a building.
Hardware Components
The following components are required to make Radio Transmitter Circuit
| S.no | Components | Value | Quantity |
| 1. | NPN Audio Amplifier Transistor | NTE123A | 1 |
| 2. | Crystal socket | – | 1 |
| 3. | Mic | – | 1 |
| 4. | Antenna | – | 1 |
| 5. | Inductor or Coil | 10 turns | 1 |
| 6. | Capacitor | 0.001uF, 50pF Trimmer | 2, 1 |
| 7. | Resistor | 10kΩ, 47kΩ, 330Ω | 1, 1, 1 |
| 8. | Battery | 9V | 1 |
NTE123A Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of NTE123A
Radio Transmitter Circuit
Working Explanation
This 27 MHz Receiver circuit operates with the help of an NTE123A, an NPN sound amplifier transistor. The NTE123A enhances the sound signals to the desired value. The circuit utilizes the crystal socket, walkie-talkie type antenna, and a mic in the circuit. To tune the circuit to its maximum yield power alter the C3 50pF trimmer capacitor in the circuit.
Therefore, if the radio isn’t starting steady, gradually adjust capacitor C3 until the sound signal becomes steady and consistent. The circuit operates by a 9V battery. Moreover, an inductor of 10 turns of # 16 enameled wire twisted on a 1/3 inch rod is also fabricated with the circuit. Therefore, if you need to utilize the circuit on just a single frequency, at that point remove the crystal socket and directly retrofit the crystals of desired frequency on the circuit.
Applications and Uses
The uses of these 27MHz Radio transmitters are:
- Produce an RF carrier wave
- Amplify the carrier wave
- Modulate the sound wave, digital signals, or some other forms of data signals
