Some weird tubes

Toobs were cool.

Krytron, used to trigger the initiators in the original nukes:

Acorn tube:

Distributed-deflection CRT

And some proximity fuze tubes, shot out of cannons at 20,000 G's

"John Larkin" wrote in message news: snipped-for-privacy@4ax.com...

I've got some late 80s vintage JAN submini tubes (same style, not sure if they're the 20kGs type though). Handy, when all you want is a triode (or whatever). Sure are pricey compared to, say, 12AX7s though (glad I didn't have to pay for 'em ;) ).

Tim

A bit odd, but trigger tubes, thyratrons and so on weren't all that uncommon.

Strange that they call them "thyratron" when they are cold cathode. I don't think you can call it that if it's not heated.

Defining characteristic of a thyratron is the same as the SCR: it can be latched "on" in the forward direction, and doesn't conduct in the reverse direction.

I have some 2D21s, which are capable of nearly 100W of phase control, not bad at all for a miniature 7 pin tube.

Could be any number of computer/mil/aero/spook applications, I suppose (triggered panel indicator?). Not entirely outlandish: I have one of the strange-looking strobotrons,

Cool, that could do some interesting things. Negative plate resistance, positive feedback, latching, oscillating; not sure how fast really (despite pulse applications being suggested). Good transconductance, definitely a later production (1961 it says?) frame grid type.

Mixer or control (wired-OR?) applications?

If they're the individual-cathode, tight-fitting-anode construction, they should have high perveance, so if for some reason you wanted a six phase

Yummy. Spark it up and enjoy the blue glow (responsibly ;) ).

They're the best, of course!

Tim

This is the vertical deflection section of the CRT used in the Tek 519 scope. That was a 1 GHz scope with no vertical amplifier, a really bizarre creation.

It used single-ended deflection, with a delay-line deflection plate inside that box.

The horizontal deflection amp used some big transmitting tube.

The spiral thing is a delay line with the speed matched to the speed of the electron beam between the plates, so the deflection voltage and the beam advance in sync.

This was done to get enough time to turn the beam when the input was so fast that it turned the beam back durin the time of traversing the deflection plates.

I did not quite see if there is a row of deflection plates attached to delay line taps.

The idea of split deflection plates maybe came from distributed tube amplifiers, where several tubes were paralleled using delay lines, also used in tube-age Tektronix scopes.

More likely three phase rectification with a common cathode (cathode is the positive electrode).

A more interesting configuration was a mercury rectifier with the (positive) electrode at the bottom of the mercury pool with 6 anodes for a three phase full phase rectifier (center taps transformers for each phase grounded) provided +600 V for a trolley buss line. When a bus was climbing a hill, there was quite a lot activity between the mercury pool on the bottom and the anodes.

check out this short video

Don't leave out the old 7360!

That was a beam tube with electrostatic deflection to steer the current to a pair of plates; it was a single-tube equivalent to a Gilbert cell mixer/modulator/demodulator (or Howard Jones cell...)

It has an enviable dynamic range, and (at 7 electrodes plus heater) is simpler than the solid-state equivalent.

Well, more like a CA3028 than an MC1496 or what have you.

However, if you were to cascode two above one... :)

Also way better isolation due to all the shielding / screening action of the grids. Same with the heptode, except single quadrant.

Tim

absent any magnetic or electric fields

in

Wikipedia credits the original invention of the distributed amplifier to Bi ll Percival of EMI Central Research in 1936. He was still working there - r ather productively - when I was there from 1976 to 1979. I even had a profe ssional interaction with him once, but couldn't give him the answer he want ed.

It's widely regarded as a very good idea. The Tektronix scope may have poac hed the idea second hand from travelling wave amplifier tubes, whose intern als look rather similar.