Tunnel Diode

Just tell your professor that his questions are irrelevant because you can't buy tunnel diodes anymore.

I am going to have to chastise my wife, who dumped my basement stock of old parts about 20 years ago. There were several tunnel diodes in there. She also liberated my several boxes (about 6 cu. ft) of vacuum tubes, dating back to the '20s and up through the peak of tubes.

But just think of how much freer you have been ever since!

Rick

My wife had me donate a lot more vacuum tubes than that. Two boxes full, each 4'x4'x3', to a radio club back east. No charge. Just sent them. Everything from tubes I'd liberated from 1944 radar systems (VR-150, for example) to more modern TV and radio tubes, including some miniatures. Stuff I'd been collecting since I was about 11 yrs old. I think they were put to good purpose.

Jon

... snip ...

I would have been much happier with such a disposition. Mine were just dumped. I didn't even know about it for months. BTW, a VR150 is a modern tube, to me.

One can dump a DC bias current into the TD, maybe through an inductor, just below the peak current. Then add the signal pulse current, maybe through a small capacitor. If the bias+signal current sum exceeds the peak current, the TD will switch to its high-voltage operating point.

The whole thing can devolve to a resistive bias network, one inductor, and one capacitor. A small, fast incoming pulse can be made to kick the TD into its high state for some time, microseconds or whatever. So it becomes a threshold detector+one-shot.

You can also make a sampling ocilloscope based around a TD peak detector.

Too bad you essentially can't buy TDs any more. They were cool. You could buy a TD with a 20 picosecond switching time in 1970.

Why do you want to know?

John