This circuit contains an IC but it looks like a 3-leaded transistor and that's why we have included it here.The IC is called a "Radio in a Chip" and it contains 10 transistors to produce a TRF (tuned Radio Frequency) front end for our project. The 3-transistor amplifier is taken from our SUPER EAR project with the electret microphone removed. The two 1N 4148 diodes produce a constant voltage of 1.3v for the chip as it is designed for a maximum of 1.5v. The "antenna coil" is 60t of 0.25mm wire wound on a 10mm ferrite rod. The tuning capacitor can be any value up to 450p.
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