There’s been a spate of apocalypse related articles over the last few weeks, but when I saw an AM radio made from a hand-wound coil and an oxidized British penny, I couldn’t help but be impressed. We’ve covered foxhole radios, stereotypical radios that are cobbled together from found parts during wartime.
This example uses a variable capacitor for tuning, but that’s technically optional. All that’s really needed is a coil and something to work as a diode. Surprisingly, copper oxide is a semiconductor, and the surface oxidation on a penny is enough to form a rudimentary diode. Though, note, not all pennies have that necessary coating of copper. If a penny has green oxide, it’s likely a candidate.
Need a quickly cobbled together AM radio? Have some wire and a penny? Yeah, watch the video below the break, and you’ll know how to make it happen. When the apocalypse comes, you’ll thank us.