AM Radio Receiver

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!

Breadboard prototype

Circuit

The MW coil

Schematic