One transistor FM receiver

One transistor FM receiver

In this exciting project, not only will you have a very unique one transistor FM recevier, but also be in-store for making home-made air-core coils and a home-made fixed capacitor. And even more than that, when you finish ‘your’ project, your journey has just started. With your now-working FM receiver, you can start experimenting with other wonderful things.There are 12 component count on this project. One transistor FM receiver


at http://www.somerset.net/arm/reprints/radio_shack_special/rss.html

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Schematic diagram for the One Transistor FM Radio with Improved Audio Gain

Schematic diagram for the One Transistor FM Radio with Improved Audio Gain

One Transistor FM Radio with improved audio gain.




Some wiring notes:




Unless you have experience with super-regenerative radios, I highly recommend using the FAR Circuits printed circuit board.



Connect the two sections of the variable capacitor (C3) in series to linearize the tuning somewhat. That is, use the connections on either end of C3 and don't use the middle lead.
L2, the RF choke should not be near a ground. The same is true for L1. Capacitance to ground will disturb the feedback.

The gain is just enough to drive an earphone. If you live too far away from radio stations, you might have trouble hearing one. There is no option here for an external antenna (that would require and extra transistor).

You can drive a speaker if you add an external audio amplifier.

If you want a little more audio gain, or you cannot locate a TL431CLP chip, you can use some other audio amplifier in the circuit where pins 1 and 2 of D1 normally connect. You can use an LM386 or a TDA7052 audio amplifier. Quasar DIY project kit #3027 is a complete TDA7052 audio amplifier kit and it works fine in this application.

source : http://www.somerset.net/arm/fm_only_one_transistor_radio.html

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