crystal radio: the first real free energy device

[profitis]

1. PbS( a lump not in a diode configuration) is an insulator until a critical voltage (band gap) is applied, then it becomes a conductor. Correct?

I think this only applies to light of that bandgap energy.

2. The catwisker acts as the p type semiconductor, creating the diode with the n type galena?

Correct

3. How is the p type formed, is it an oxide on the metal? It can't be pure metal only correct?

Its the pure metal.a depletion-schottky zone is formed in immediate vicinity metal/semiconductor

4. Why is a fine point needed, as a thick wire turns the diode into  a normal conductor?

Something to do with accumulation of charge at a point?

5. Why does some galena conduct well both ways with the same catwisker that works well on another sample.

This is beyond the scope of this text-book

Some semiconductors eg tellurium conduct far better parallel to its own crystal plane than across its crystal plane. Try putting a magnet near the galena and see if the hall-effect does anything to the power pomodoro

[pomodoro]

Thanks. Well I've only got one quartz tube left to melt the galena. Moreland used 10:1 or 20:1 PbS : UO.



Too much apparently stops the PbS recrystallizing.



I'm not sure how to make synthetic galena as good as natural.

[profitis]

Excellent I wonder what effects it will have.go easy with that last tube pomodoro

[pomodoro]

This is what the melted galena looks like.  I will dope this same batch for a direct comparison.

[profitis]

Nice