Thyratron

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psycho
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Thyratron

Post by psycho » Mon Dec 29, 2008 6:39 pm

Like I always do when I am ________ (bored, curious, etc... Fill in the blank), I was nosing around wikipedia and ran across this gizmo. Never heard of one before.

If, as I understand it, the transistor replaced the vacuum tube, that would mean that a MOSFET is a solid state Thyratron???

You can read about it here:
http://en.wikipedia.org/wiki/Thyratron

The first part (...used as a high energy electrical switch...) is the basic definition of a MOSFET as far as I know (but then again, I know so little)

Kevin

sghioto
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Post by sghioto » Mon Dec 29, 2008 7:00 pm

psycho,

The SCR and TRIAC are the solid state replacement. Did you read the whole article?

Steve G.

psycho
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Post by psycho » Mon Dec 29, 2008 7:10 pm

No, actually, I got side tracked and never got back to it. I should have read the whole thing before putting my foot, er ... saying anything. :shock:

But, thanks, though!

psycho
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Post by psycho » Mon Dec 29, 2008 7:14 pm

Did the MOSFET replace something unique or just a type of tube?

Excuse my ignorance, I have never used a tube (and I hope I never do).

Thanks,
Kevin

Robert Reed
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Post by Robert Reed » Mon Dec 29, 2008 7:36 pm

The mosfet replaced the tube just as the transistor did, only operates on a little different principal (much like the tube) which is transconductance. However when looking at the transistor as replacing tube type triodes, the mosfet with dual gate elements could be viewed as replacing the tube type tetrodes.

k7elp60
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Post by k7elp60 » Tue Dec 30, 2008 6:17 am

Thyratron, ah I remember them somewhat. A vacuum tube filled with gas that when triggered on a grid, current would flow from cathode to plate and they would glow. A couple of numbers might have been 4C35 and 2050. They were used like SCR's today.

Bigglez
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Re: Thyratron

Post by Bigglez » Sat Jan 03, 2009 12:09 am

psycho wrote: If, as I understand it, the transistor replaced the vacuum tube, that would mean that a MOSFET is a solid state Thyratron???
The transistor replaced valves (tubes) due to commercial
rewards (size, cost, simplicity of power supplies, portability).
The transition for electrical engineers schooled on valves
was a steep learning curve.

Basically a valve is a voltage controlled resistor (like a FET)
and a transistor is a current controlled resistor, not very
linear, and prone to self-destruction (thermal run away).

FETs were discovered before transistors, but had to wait
until the semiconductor industry 'caught up' to be
a commercial product.

A Thyratron (or the similar Ignitron) is a voltage triggered
switch, and does its best work in high power circuits.

Present day examples are to be found around the
semiconductor equipment industry (for high power
spluttering and plasma etching and cleaning duties)
where MOSFets wouldn't be economical.

I have one or two in the 'serious glass' gallery of my
valve museum. I think they're sexy. About the size
of a thermos flask! Although the tiny ones are/were
associated with nuclear weapons.

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Karl Williams
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Post by Karl Williams » Wed Jan 07, 2009 12:30 pm

Hi Bigglez,

Can you post some pictures of your valve museum?

Bigglez
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Post by Bigglez » Wed Jan 07, 2009 1:37 pm

Karl Williams wrote:Can you post some pictures of your valve museum?
Sure, and Happy New Year! (Haven't seen you post here for a while - what are you working these days?)

I don't have access to all my PIX form here, so this is a
taste... (plus I don't want to clog this forum - not sure
many of us are into hollow state electronics)
Image
(1) Minature TV CRTs typically used in TV camera viewfinders.
Far right is a 40mm tri-phosphor colour CRT (world's smallest?)

Image
(2) Video camera tubes.

Image
(3) Amglo low pressure 'strobe' tubes

Image
(4) Four generations of TV camera tubes:
(L to R)Plumbicon 1963, 3 ins Image Orthicon 1941, 4.5 ins Image Orthicon 1959, Iconoscope 1939

Image
(5) Serious Glass Collection (circa 2002)

Image
(6) Annual Cleaning

Image
(7) A pair of Eimac 100th/VT218 75W RF Triodes
(Rare to find two with intact filaments!)

Image
(8) 330mm Photoplotter magnetic Deflection CRT and frame

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dacflyer
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Post by dacflyer » Wed Jan 07, 2009 6:15 pm

very nice glass !
i wish you was local, i'd love to see more,and up close..
in pic 3. are theose a type of strobe tubes ?

and in pic 5 in the glass case, what tube is that in the very lower right with the big pins?

and in pic 8, whats that thing :D

in the glass case i also seen some nice lamps too.. i like and miss the 1,500 watt incadescent lamps. you only can find quarts lamps that bright now days @ 220V. i liked the big bulb 115v versions for 2 reasons..
as a yardlight,. they lit up instantly, and unlike a HID, they came back on instantly if needed. HID's you almost have to wait 20 min for a restrike.

Bigglez
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Post by Bigglez » Thu Jan 08, 2009 12:19 am

dacflyer wrote: in pic 3. are theose a type of strobe tubes ?
Yes (and no...) On the left is a very rare neon
indicator that was used in only one product -
The 1937 Mills Studio jukebox as visual displays
for tone controls. The other three are low pressure
discharge tubes from Amglo. These were used for
strobes but also (and more likely) for decoration.
These are the inventions of Andrew F. Henninger, Jr.
(Who held many patents in this field).
dacflyer wrote:pic 5 in the glass case, what tube
is that in the very lower right with the big pins?
A tungsten "sand bulb" used in movie set
lighting. At the end of the day the glass would be
dark from tungsten deposits. The cure was to agitate
the bulbs in a machine. The tungsten granules sealed
in the glass envelope swirl the deposts off!
dacflyer wrote:pic 8, whats that thing
A precision CRT (probably used for photoplotting).
The face is a 330mm (12 ins) round bulb. The
deflection coils and various beam alignment coils
are on precision metal slides for "tuning" the spot
size and astigmatism. There's a video amp on the
CRT socket. The frame is about 900mm (33 ins) long!
The CRT was constructed by Thomas Electronics
in Wayne, NJ.
dacflyer wrote:in the glass case i also seen
some nice lamps too..
Yep. I have several more but they're too big to
fit my current display cabinet. I've added a
couple of "serious glass" triodes (in the 1500Watt
class). Some of the bigger ones are in a storage
locker, along with X-Ray tubes and a bunch of Tek
CRTs and few other odds and ends. I don't like the
ceramic/metal power tubes, and the all glass are
typically pre-WWII and under 2kW.

I have a non-working VT- 122/ WL-530 triode
(the grid collapsed) from an SCR-270 Radar
(Not the one that famously failed to accept the
detection of the invading Japanese air strike
on Pearl Harbor). Nice glass, nice providence.

I've seen the actual SCR-270 radar as its now
on display at a private museum in Baltimore, MD.
dacflyer wrote: i like and miss the 1,500 watt incadescent lamps. you only can find quarts lamps that bright now days @ 220V. i liked the big bulb 115v
Yes, we witnessesd the evolution of the
"Edison" lamp from its maturity and mass production
to almost total obsolescence in a human lifetime.
dacflyer wrote: yardlight,. they lit up instantly, and unlike a HID, they came back on instantly if needed. HID's you almost have to wait 20 min for a restrike.
I have a hole in my collection as I've not found a
low pressure sodium vapor/neon start lamp.
They have been used for street lighting for decades.
Most contemporary sodium lamps are high pressure
types.

You would certainly be welcome to visit! Any collection
should not be kept hidden from visitors!
I've edited the pics to add your numbers (duh...I
should have made captions the first time).

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evahle
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collection

Post by evahle » Thu Jan 08, 2009 7:30 am

Nice pictures and collection Bigglez.

evahle :smile:

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dr_when
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Post by dr_when » Thu Jan 08, 2009 11:59 am

Bigglez,

Very nice collection and photos too!!! Something pretty cool about that era despite the heat.

Bob
"Who is John Galt?"

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Karl Williams
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Post by Karl Williams » Thu Jan 08, 2009 12:22 pm

Hi Bigglez,

Thanks for posting the pics - nice collection!
The first O-scope I ever owned was a really old heathkit tube model and one of the things I liked about it was the smell of the hot tubes.
The clock source for the scope was the 60 Hz from the AC line - LOL.

Robert Reed
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Post by Robert Reed » Thu Jan 08, 2009 1:48 pm

When I first started out, there was nothing that could match the feeling of peering into the backside of a large dimlit cabinet. The soft glow of tubes and occasional clicking of relays was pure magic and I was in awe!

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