KBr Crystal Amplifier

[tansis]

It's been a few weeks since my last bout of cranial anarchy so I think another brain teaser is in order, well more of a quest this time.

Delving into the history of the transistor and semi-conductor theory one will find repeated references to the work of Robert Pohl and Rudolph Hilsch. Now back in 1938 they claim to have created a three electrode (Potassium Bromide) crystal amplifier, with a reputed current gain of 100 to 1 and some rather curious operating properties, however its performance made it unsuitable for many uses such as RF and audio amplifiication, so it was banished to history, well almost.

What I would like to know is..
Has anyone managed to build a duplicate device in more recent times?

 

[Russlk]

Is there any record of how they did it? I once tried to make a transistor by adding a 2nd point contact to a 1N34 crystal diode, but I didn't know what I was doing and it did not work.

 

[Sebi]

Just for curiosity...

 

[tansis]

Have yet to find any detailed info myself, I intend to have an hour or two trawling through the Patent Office website some time over the weekend.

Sebi has found a remarkable piece of history from the Bell Telephone Laboratories, a copy of the orginal notes for the first transistor dated December 1947

Want to make your own transistors ?, try this link for inspiration...
**broken link removed**

It takes a while to load but the images at the bottom/end of the page are fascinating.