ΠΩΣ ΦΤΙΑΧΝΟΥΜΕ ΕΝΑ ΡΑΔΙΟΦΟΝΙΚΟ ΣΤΑΘΜΟ ΣΤΑ FM?

How to Make FM Transmitter?

This tutorial is for making simplest FM transmitter using only one transistor. VC1 is a small, screw-adjustable, trimmer capacitor and its rating should be around 10-100pF. Set your FM receiver for a clear, blank station.

Then, with a non-conductive tool, adjust the capacitor for the clearest reception, rotate it till the receiver receives a sound from the microphone of transmitter. Use the following formula for determining the frequency.

The schematic of FM transmitter:

The following shows the components used to make FM transmitter:

1. Transistor, 2N3904:

2. Capacitors, 4.7pF, 20pF, 0.001uF, 22nF. (0.001uF has code 102 and 22nF has code 223)

3. Variable Capacitor, For VC1 you can use a trimmer capacitor that looks like this:

4. Resistors, 4.7K, 470R

5. Mic, Condenser Electret Microphone:

 

6. Inductor, 0.1uF 6-7 turns using 26SWG wire:

Learning how to make an inductor for FM transmitter:

You need to scrap the ends of inductor, otherwise, the inductor does not work, you can use commercial 0.1uH inductor.

Assembly:

Insert transistor, resistors and capacitors on breadboard. You can see the values of the components on the previous picture. Then insert electret microphone. Use 15cm long antenna. You can use a normal wire for antenna.