Just like they did it in the early 1900's... Galena touched gently with a cat's whisker.. You have to play with it a little to get a clear signal... Neat thing about this crystal...
Reverse it and it works the same... Can't do that with a 1n34A! You can still get the real thing, but the price has gone up since I bought this over 15 years ago...You can fine these at antique
electronics. It goes to show you the a Junk box is a treasure chest!