(To those who swear I've covered this topic before: I have; I just wasn't satisfied with my original video)

Remarkably simple and requiring no power source, crystal radios were the primary means of listening to commercial radio broadcasts until the late 1920s and early 1930s, when they were largely superseded by more sensitive tube-based heterodyne and regenerative receivers. However, they continue to be built by hobbyists and are a popular project for teaching children the basics of radio technology.

Huge shout-out to Julian Horn and United Nuclear for their invaluable assistance in putting together this video. Check out United Nuclear's fascinating catalogue at: unitednuclear.com

Medical Coils/Batteries Video: https://youtu.be/NufNhuWI1iA

0:00 Introduction
0:52 Spark Gap Transmitters
2:02 Coherer Receivers
3:05 Magnetic Hysteresis Detectors
4:38 Reginald Fessenden and the Dawn of AM Broadcasting
5:06 Parallel Tuned Circuits /LC Resonators
6:29 Rectifying/Envelope Detectors
7:23 Hot-Wire Barretter
8:19 Electrolytic Detector
9:18 Early Crystal Detectors
9:50 Crystal Radio Basics
12:17 Cat's Whisker Detectors
12:56 P/N and Metal-Semiconductor Junction Diodes
14:39 Later Crystal Detectors and Diodes
16:26 1923 Ariel Crystal Set
17:11 Self-powered Crystal Radios
17:50 Crystal Radio Optimization and Range
20:52 Foxhole Radios
22:27 Obsolescence of Crystal Radios
23:05 1950s Miniman Rocket Radio
24:18 Outro

SOURCES:

https://web.archive.org/web/20121228200010/http://www.ieee.ca/millennium/radio/radio_differences.html

https://earlyradiohistory.us/1917de.htm

https://eng.libretexts.org/Bookshelves/Materials_Science/Supplemental_Modules_(Materials_Science)/Semiconductors/Metal-Semiconductors_Contacts

https://www.radiomuseum.org/r/graves_ariel_crystal_set.html

https://www.electronics-notes.com/articles/radio/radio-receivers/how-does-crystal-radio-work.php

https://www.electronics-notes.com/articles/history/radio-receivers/cats-whisker-crystal-radios-sets.php

https://www.nutsvolts.com/magazine/article/remembering-the-crystal-radio