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How to Build an IC FM Tuner Receiver

FM tuner receivers are electronic devices designed to capture radio signals from the air and play them through a small speaker. In the old days of radio, assembling a receiver required large vacuum tubes and a good chunk of your desktop space. Now, specially designed integrated circuits that measure less than an inch long do the bulk of the radio's work. Hobbyists need only add on a few more components such as resistors, antenna and speaker to make a complete unit.

Things You'll Need

Breadboard
Printed circuit board (PCB)
Printer
Transfer paper
Iron
2 bowls
Tweezers
Etching solution
Acetone
Q-tips
Power drill
Soldering iron
Solder
TDA 7021T integrated circuit
Antenna
22K ohm resistor
2.2K ohm resistor
4.7K ohm resistor
51pF capacitor
9018 transistor
100pF capacitor
Coil
25pF variable capacitor
3 100n capacitors
2 10n capacitors
3.3n capacitor
220 pF capacitor
4700 pF capacitor
1000pf capacitor
1500 pF capacitor
2 10uF capacitors
22 20 uF capacitors
LM386 integrated circuits
Headphones

Instructions

- 1
  Select an FM tuner receiver circuit. Since this is a common beginner-level project, innumerable tutorials are available on building FM circuits with free circuit schematics. Each schematic is generally built around a specific IC such as Philips's TDA 7021T IC.
- 2
  Collect the components needed for this circuit. For a list of the components for this project refer to the "What You Will Need" section. In addition to the TDA 7021T IC you will also need the appropriate resistors, transistors, capacitor and an antenna. Also since the volume output for this circuit is relatively low, an amplifier circuit is built into the unit. See the second Resources link for the amplifier circuit diagram
- 3
  Assemble the circuit on a breadboard. This is an excellent way to test your connections before commencing the soldiering process. Never assume that a circuit works until you have seen it with your own two eyes.
- 4
  Draw the circuit on a computer-aided design program. Cadsoft's EAGLE (Easily Applicable Graphical Layout Editor) is a robust, affordable circuit design program that allows hobbyist to draw diagrams quickly and accurately.
- 5
  Print the diagram onto PCB transfer paper using a laser printer.
- 6
  Apply the copy of the circuit diagram, face down onto the copper side of the PCB. Then place a hot iron on top of the drawing for three minutes. Remove the iron and soak the PCB in hot water for about 30 minutes. Take the PCB out of the water and slowly remove the transfer paper. A drawing of the circuit in black ink should remain on the PCB.
- 7
  With tweezers, place the PBC in the etching solution. Allow to soak until all of the copper except for that covered by the black toner has dissolved away. With tweezers, remove the PCB from the etching solution. Using acetone and Q-tips, slowly wipe the black toner from the remaining copper.
- 8
  Drill holes in the PCB where the wire leads of each of the electronic components will run through the board.
- 9
  Attach the components to the PCB. First place the components' wire leads through the appropriate holes. Then solder the lead to the circuit board. When finished soldering, use a wire cutter to snip off the excess wire.
- 10
  Attach a power supply and test the circuit.

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