Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

Reading about old-fangled radios the reference quoted below indicates it was/is possible to use a rusted razor (or perhaps any similar thin corroded metal strip) as a detector.

Some resourceful GIs found that a crude crystal set could be made from a coil made of salvaged wire, a rusty razor blade and a pencil lead for a diode. By lightly touching the pencil lead to spots of blue on the blade, or to spots of rust, they formed what is called a point contact diode and the rectified signal could be heard on headphones or crystal ear pieces.

How does a rusted razor perform the same task as a PN junction? Is it merely that rust (being minute oxidized metallic particles) migrates under the influence of the electrical field?

share|improve this question
add comment

1 Answer

up vote 1 down vote accepted

This isn't a great answer since all the papers I could find are behind paywalls, but ferric oxide is a semiconductor and depending on it's exact stochiometry can be n type or p type.

If you know someone in academia with access have a look at:

http://jes.ecsdl.org/content/126/3/419.abstract

http://jes.ecsdl.org/content/131/8/1777.abstract

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.