Similar to the Radio Microphone, in this post I will show you how to build your very own radio transmitter by replacing the Microphone with a 3.5mm headphone jack. This can be used as a Radio MP3 player for your car, simply plug your phone into the 3.5mm headphone jack then tune your car radio into the same frequency as the modulator and what ever is playing on your phone will be broadcast to the car radio. So go ahead and get creative!

 Tools Required:

• Capacitors
  • 4x 1nf
  • 1x 10pf
  • 1x 33pf
  • 3x 47uf
• Resistors
  • 2x 47k
  • 2x 22k
  • 1x 39k
  • 1x 100r
• Transistors
  • 2x 2n3904 ebc OR bc547b cbe
• Trimmer Cap 30pf
• Printed Circuit Board (We recommend using an original PCB a plastic board but if you don’t have one  you can use a piece of cardboard)
• Antenna 15cm
• Coil 5turns
• Frequency 88mhz – 108mhz

Diagrams:

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