Uploaded June 2012 | Updated September 2026, 3 weeks ago

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Step-by-step details for how to make an amplifier for a crystal radio earphone or earpiece. This includes information about electrolytic and non-electrolytic capacitors, how to use a breadboard, and how to determine the emitter, base and collector for a transistor. I also talk a bit about how the transistor works to make the amplifier circuit work. The crystal radio amplifier circuit is shown and explained.

This video has correct English captions. Click on the CC button at the bottom of the video to see them.

The parts needed are:
- resistors: 82 kilo ohm, 100 kilo ohm, 10 mega ohm
- capacitors: 0.001 microfarad, 2 x 1 microfarad, 10 microfarad
- 2N4401 or equivalent transistor. tom leroux reported that 2N3904 and 2N2222 also work
- 9 volt battery

See also this video, "Steps for How to Make Amplifier for Crystal Radio Earpiece", which shows every step as I make this amplifier, showing where I put each part in the breadboard:
youtu.be/V0dKdSNv_dY

Step-by-step instructions to make the crystal radio are here:
youtu.be/VqdcU9ULAlA

Additional crystal radio troubleshooting tips are here:
youtu.be/HZZmKZJrIW0

A video on how to make a crystal radio coil with taps is here:
youtu.be/Gi9EmhrcfIg

Charles Wenzel's website is:
techlib.com/electronics/crystal.html

My own webpage about crystal radios is:
rimstar.org/equip/crystal_radios.htm

Follow me on Twitter:
twitter.com/#!/RimStarz

rimstar.org