Single-Transistor AM Radio

Tune in to amplitude-modulated broadcasts with one transistor, one diode, and a hand-wound coil — radio at its most beautiful and minimal.

Difficulty: Breadboard. Estimated build time: about 60 minutes. Estimated parts cost: about US$4.80. 10-part bill of materials with live supplier pricing. A working AM broadcast receiver tuned across 530–1600 kHz with one NPN transistor and a Schottky/germanium detector diode.