Hello, radio funs! Here is a super simple transistors-only radio receiver. This is a pretty cool AM radio you can build.
What are the benefits and disadvantages of the circuit?
- you can use low impedance headphones;
- there are no $5 chips, only basic transistors;
- only one AAA battery or even a coin battery power;
- good selectivity and gain.
There is also and a disadvantage – keep a 2 cm distance between the coil and the board to avoid self-oscillations. Cover the board with a metal shield.
The first schematic was published in the Russian radio magazine, check the ref.: "The Radio", 1993 #09. I tweaked and tested the schematic with popular 2n3904, 2n3906 transistors, and also with the 2n2222, 2n2907. There is no big difference at all, you can use any general-purpose transistors that you have on the desktop. I picked a lot of stations in the evening and even a couple of them in the morning (East Europe). It's a pretty loud radio!
PS. I built this project when I was a ten or eleven years old kid. Build with kids and have fun!
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| Breadboard prototype |
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| Circuit |
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| The MW coil |
Schematic
