A diode is an electrical device that allows power to travel in only one direction.
Diodes can be made of Silicon, Germanium or even copper oxide.
Note: The there is only one alligator clip connected to that wire, the other is an illusion.

Step 1: Aquiring Copper

I used some copper wire 6 inches (14CM), use any fair size (22AWG or larger) copper wire with all insulation striped off.
Wash it in clean (preferably distilled) water.

Step 2: Making Copper Oxide

You will need alot of heat ;)
The best solution is to put it in a propane torch glowing red for a minute or two.
Hold it with pliers!
You may be able to use another heat source but the copper needs to turn red.

Step 3: Making the Diode

Carefully clip an alligator clip to one end and loosly wrap a piece of wire around the other end.
Avoid damaging the black/red oxide layer.

Step 4: TEST!

I used two AA batteries and a digital meter:

Has anyone tried using one of these for a crystal radio?&nbsp; It is akin to the old foxhole radios with the oxide on the razor blade preforming this function.<br />
<span class="medium_text" id="result_box"><span style="background-color: rgb(255,255,255);" title="">Many years ago I had a turntable that due to poor contact acting as a diode, captured an AM radio station. </span><span style="background-color: rgb(255,255,255);" title="">At times you could hear perfectly, like a radio instead of a turntable.<br /> <br /> </span></span>
In step 4 you are showing that the current flow through the diode in one direction is different than in the other direction.&nbsp; Is that correct?<br />
Yes, Notice the - sign, you will see quite a bit more volts foreward vs backwards.<br />
Once the copper is red hot you can stick it&nbsp; quickly in some water. The red oxide will form very quickly but there is the danger of steam. I found this out with I smelted copper with a arc furnace and then kicked the blob in water. The grey outer coating quickly turned a nice red color. I still have the blob too.<br /> <br /> <br />
Thanks for the tip!<br />

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