Si-diodes in Second World War radar & Communication equipment

Most DVM's seem to output 1 mA on the diode-test range. I don't know how much of a convention that is. They do seem to disagree on how much voltage they'll indicate: some display the Vf of an LED, some say open or overload or whatever.

John

"John Fields"

BTW:

how hot did you make it get first ?

.... Phil

Thanks for the references, John. Sounds like Buderi, who certainly had access to all that, might have put it in somewhat different light than he did, perhaps something along the lines of, "though much theoretical work had been done by 1940, it remained to discover how to apply it in practice." He does make it clear that researchers all the way up through development of the transistor didn't fully appreciate what they could do with potential barrier diagrams and Fermi levels and the like. As I scan through the book, I see multiple references to events over several years where there was clear puzzlement, limited understanding, and/or disagreement about what was going on in observed effects around semiconductors. The serious search for a solid-state amplifier (based on semiconductor materials) was started apparently at least by 1936 at Bell Labs, and I suppose it was there and at a very small number of universities where much of the published work you cite was begun or carried out. Too bad that it's a bit late to be asking the people actually involved in the work! (Wish I'd had the foresight and time to ask my uncle more about the work he did at RadLab. :-( )

Cheers, Tom

Central CMMSH1-20 is a really tiny, about 1206 size, 1 amp 20 volt schottky, great for small buck switchers; measures 201 mV at 1 mA. But it's 280 pF!

John

I think if you do a Google search for "zero bias diode" you will find things a lot more similar to 1N23 in electrical characteristics.

The radlab boys observed a number of interesting things that they didn't have the time to pursue. One was negative resistance in diodes, and another was diode mixers that had signal power gain, the precursor to the parametric amplifier. Tunneling was known, too, a long time before Esaki discovered the tunnel diode.

All that is in one book out of 27. In about 5 years, these guys invented modern electronics.

John

"Back diode" is interesting, too. They are, to my knowledge, the only germanium diodes made using an ic-type mask process, and about the only Ge diodes still made at all, except for photodiodes of course. They are still the best microwave detectors.

John

Yes, interesting, but not very much like the characteristics of 1N23.

HSMS-2850 is about 0.2V @ 1mA, but it also has a PIV rating of just 2 volts. Capacitance is considerably less than that CMMSH1-20, though. I don't have any point-contact diodes to compare it with, but can tell you that it's useful for detecting RF down to a bit below 100uV, possibly less if you're careful with thermal potentials and the like, or chop the signal.

Cheers, Tom

Not arguing that. Would that diode make a good microwave detector?

Say what you will. I was playing with 1950's (or older) parts in the

Two things, these are "modern" parts. Did the equivalent exist in the

I am getting a little tired so may blatting about modern parts as if they were available in the 1940'sand 1950's. The question is "What were the original parts made of?"

Newer implementations is, at best, a side issue.

And what is the junction capacitance and does it make a good microwave mixer?

Were germanium PN junction diodes of the period (or any later period) good microwave detectors? I thought they were pretty slow.

Well, I'm sure your memory is more accurate than my books and datasheets.

John