Medium

FM Radio Receiver Kit (Simple Crystal-Style)

An antenna, a tunable LC circuit, and a simple audio amplifier catch and play back an FM station — a classic exercise in understanding how a radio "catches" a signal out of thin air.

Circuit Diagram

Dipole antenna L C variable (tune) LM386 pin 3 IN, pin 5 OUT pin 6 VCC (+9V) pin 4 GND C out Speaker Tune the variable capacitor until a local FM station comes through

How to Build It

  1. Connect the dipole antenna to a tunable LC tank circuit (coil + variable capacitor).
  2. Connect the LC circuit's output to an LM386 amplifier's input.
  3. Power the LM386 per its standard wiring (pin 6 to +, pin 4 to GND).
  4. Connect the LM386's output (pin 5) to a small speaker, through a capacitor.
  5. Tune the LC circuit (turning the variable capacitor) until you catch a local FM station.

Bill of Materials

ProductCodeQty
Antenna family 68850 1
Inductor MCQ1V1608-R470-R 1
Speaker cable KAB0352 1
Integrated circuit LM380N-8 1
Capacitor (electrolytic/ceramic/SMD/film) 1
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