Shinichi Uno

Dr. Don Bowyer
MUA 401
November 19 2007
Final Report

Project title: Electrical kit construction

Name of the kit: MP3 / Walkman FM Transmitter

Description: This is a mono FM transmitter that is specially designed to be connected directly to the headphone output of your Walkman or any other type of audio source such as a computer or MP3 (also iPod) player with a headphone jack. The sound is then broadcast through the transmitter, and plays through an FM frequency. Purposes for an FM transmitter include playing music from a device through a car stereo, or any radio without an audio input jack. The transmitter is easily tunable to the FM band (88 – 108 MHz) using an adjustable coil and is stable in frequency. The kit includes a battery holder as well as a built-in stereo jack and plug-to-plug stereo cable for easy connection to any stereo audio source.

Components:

• Ceramic Disc Capacitors
  • 3 47nF
  • 1 390pF
  • 2 7pF
  • 1 47pF
  • 1 6pF
  • 1 10nF
  • 2 1nF
  • 1 100pF
• 3 Terminals
• Radical Resistors
  • 1 15kΩ
  • 2 5.6kΩ
  • 1 1kΩ
  • 3 560Ω
  • 2 100kΩ
  • 3 100Ω
  • 1 43kΩ
  • 1 4.7Ω
  • 1 27kΩ
  • 1 470Ω
• Stereo Jack
• Inductor
• 2 TO-92 Transistors
• 5-pin Coil
• LED
• Slide Switch
• Antenna
• Battery holder
• 2 screws
• Circuit Board

Although the kit is so tiny, it is not so hard to solder. The thing, however, I needed to care was to solder the radical resistors. As the below picture shows, the resistors should be mounted in some parts.

Below is the completed circuit.

In this project, the worst problem I met is that the transmitter did not work. I tested the circuit as the assembly guide says, and re-soldered everything. But the kit would not work after all though the LED was lit.