USB FM Transmitter

USB FM Transmitter Circuit

USB FM Transmitter is designed small and powered from the USB port. You can use this FM transmitter via a laptop or personal computer to transmit your MP3 music in a radius of about 50 meters. Frequency stability of the FM transmitter is quite high because the power supply comes from the USB port. It requires 5-12V DC for proper operation.

If you have a printed circuit board (PCB) and also the necessary components, for beginners only takes about three hours to assemble. An electronic hobbyist only takes about 30 minutes to make a USB FM transmitter is ready.

USB FM Transmitter Circuit Diagram

In the FM Transmitter is no need to drill the transmitter PCB. All components will be soldered to the plate with folded leads.

Transistors and LED Leads
Transistors have a flat side. The LED leads are longer than the other is the anode (A), the other is the cathode (K).

Mono Sound
Solder the white wire and red together, set aside the yellow wire (mass). Frequency setting will change the variable capacitor slowly with a screwdriver or a thin but stiff cardboard.

FM Transmitter Parts List

• 1 Ohm resistor 510 (green – brown – brown)
• 100 resistor 1 kOhm (brown – black – yellow)
• 1 MOhm resistors (brown – black – green)
• 1 capacitor 0.1 uF (0.1)
• 1 nF capacitor 47 (0.047)
• 1 capacitor 4.7 pF (479)
• 2 pF capacitors 22 (22)
• 1 variable capacitor 1.5 pF … 15
• 2 transistor BF 246 (F246A)
• 1 red LED
• 1 audio cable (minijack)

Congratulations to experiment, and on the air with this USB FM Transmitter.

You may be interested in reading my other guides on AA Battery Charger Circuit and Power Supply Testing.