28 Oct
2007
28 Oct
'07
1:08 p.m.
Subject: Indicator tubes for transistor logic machines.
From: "Bob Shannon" <bshannon at tiac.net>
Date: Sun, 28 Oct 2007 14:03:43 -0400
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
Is anyone familiar with vacuum tube indicators used on transistor logic
machines?
I recently found a small rack filled with small transistor logic modules.
Each module holds a flip flop or two at most.
The modules are small PC boards with a metal frame and handle. Test points
give you the state of each transistor
on the module.
Several modules have some sort of visual indicator tube as well.
These tubes are not much larger than a standard NE-2 bulb, but they more
resemble subminiature vacuum tubes.
The tubes are marked 01037 J3, each had four leads. Two of these leads
shows a resistance of 9.8 Ohms, and
appears to be a low voltage filament. One is grounded, the other is
connected to a bus in the rack of logic.
There is no 'getter flash' inside the glass tube, so they may be some sort
of glow discharge tube.
Looking at the insides of each tube thee appears to be a very fine V style
filament and a grid-like structure, but
I see no clear anode or plate structures. There are two thin 'wires'
outside of the grid, one in front and one
behind the central grid-like / filament structure.
The logic itself is made from 2N414 transistors, mil-spec at one time,
covered in conformal coating. Markings
show this device came from the USAF Airborne Instrumentation Labs. I only
have a small part of some
larger system, but I would like to power this rack of logic up and see these
indicators in action.
There is something very familiar about these things. They remind me of
something I may have seen once
in a telephone switching application when I was in the USAF long ago.
Any idea what these things may be? I'll try to get a digital photo, but the
tubes are mounted under small
metal clips with short leads.
They are vacuum florescent indicators. the anode (part that will glow)
is +V applied around 16-40V range and the cathode (most minus voltage)
is formed by the two wires that are a filliment (heater to some). Some
flavors of these also have a grid between the heater and the anode and
act like a triode vacuum tube in that if the grid is sufficiently
negative compared to the cathode/heater the tube will not glow if it
is zero or positive (a few volts) the tube will glow. The transistors
are then not required to handle much voltage or current as 2n414 was
a low power alloy junction germainium (Vce of -20V and Pd of 150mW) so
it could not switch much current or voltage. Any display used had to
be operatble with less than 20V (more like 15or less) and only a few
milliamps.
I've also seen several such racks and displays down in RI. Basically
the system is built of standard logic elements available in the late
50s early 60s and an element could be a gate or Flip flop and likely
not many gates and only one FF to a card. Voltages were typically low
in the less than 15V range. The cards rarely were a complete
computer but more like a sequencer or other fixed logic system that was
designed for a specific use.
Use care powering that as power supplies may have bad caps, and wires
may be cut/shorted.
Allison
7 Nov
7 Nov
10:04 a.m.
[...] the two wires that are a filliment (heater to
some).
As I understand it, a filament and heater are not just two different
words for the same thing (for a long time I thought they were...).
A filament is what this is: the electron emitter is the same thing that
is generating the heat through ohmic losses. A heater is a case where
the heat generator is not the same thing that is emitting electrons, as
in many vacuum tubes: the heater generates heat, which then warms up
the (separate) cathode electrode.
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4:17 p.m.
[...] the two wires that are a filliment (heater
to some).
As I understand it, a filament and heater are not just two different
words for the same thing (for a long time I thought they were...).
A filament is what this is: the electron emitter is the same thing that
is generating the heat through ohmic losses. A heater is a case where
the heat generator is not the same thing that is emitting electrons, as
in many vacuum tubes: the heater generates heat, which then warms up
the (separate) cathode electrode. 
5:04 p.m.
On 8 Nov 2007 at 0:17, Tony Duell wrote:
This may be a UK .vs. US language difference, but to
me :
A 'filament' is a thin wire, heated electircally. A heater (in a valve)
is a particular type of filament
A filament that's also the cathode (as here) is a 'directly heated cathode'
A filament that heats a separate cathode is called a 'heater'. The result
is caleld an 'indirectly heated cathode'
Some of it is context-related in the US, at least. Transformers are
said to be "filament transformers" if their intended use is to power
the heater. The glow from the heater (indirectly or directly heated
cathodes) is usually said to be a "glowing filament". Many older
handbooks show basing diagrams with "F F" particularly if it's a
directly-heated cathode. The glowing element in a Tungar bulb is
usually termed to be the filament.
Finally, some call a heater a "filament" and a "cathode" the heated
emitting sleeve.
It's one of those things wherein what's intended is rarely a mystery.
"Plate" for "anode" is common usage here in all but special-purpose
devices, such as CRTs.
Cheers,
Chuck
5:39 p.m.
Many older handbooks show basing diagrams with "F
F" particularly if
it's a directly-heated cathode.
At least one databook - the one I use most, which might be where I got
the distinction - uses F for directly-heated cathodes ("filaments") and
H for the heating element for indirectly-heated cathodes ("heater").
Not that I use any vacuum-tube databook all that often these days. :-/
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8 Nov
8 Nov
11:17 a.m.
This may be a
UK .vs. US language difference, but to me :
A 'filament' is a thin wire, heated electircally. A heater (in a valve)
is a particular type of filament
A filament that's also the cathode (as here) is a 'directly heated cathode'
A filament that heats a separate cathode is called a 'heater'. The result
is caleld an 'indirectly heated cathode'
Some of it is context-related in the US, at least. Transformers are
said to be "filament transformers" if their intended use is to power the heater. The glow from the heater (indirectly or
directly heated
cathodes) is usually said to be a "glowing filament". Many older
handbooks show basing diagrams with "F F" particularly if it's a
directly-heated cathode. The glowing element in a Tungar bulb is
Sure. That _is_ a filament :-). Some data books use 'F F' for a
direcrly-heated cathode and 'H H' for a heater, with 'k' for the cathode
itself. Oh, and 'Hct' for Heater centre tap :-)
usually termed to be the filament.
OK, it's not thin, but I think it's a filament :-)
Finally, some call a heater a "filament" and a "cathode" the heated
emitting sleeve.
In context, I'd used 'heater' for the hot wire and 'cathode' for the
sleeve around it
It's one of those things wherein what's intended is rarely a mystery.
Exactly. If somebody talks about the 'cathode voltage' of an
indirectly-heated valve, it's clear they mean the voltage between the
emitting sleeve and some reference point/. Whereas 'heater voltage'
would normally mean the voltage between the ends of the heater filament.
"Plate" for "anode" is common usage here in all but special-purpose
devices, such as CRTs.
That is not at all common over here. Most old-timers would know what you
meant, but it would be taken as an Americanism.
Talking about CRTs, I beleieve across the Pond, the electodes are called
'cathode', 'grid 1', 'grid 2'.... 'anode'. Over here
they're 'cathode'
'grid'. 'anode 1' (or 'first anode'), 'anode 2'
('second anode')... (the
last one, the aquadaq coating inside the flare, connected to the EHT
supply, is called the 'final anode' most of the time).
-tony
2:32 p.m.
On Thu, 8 Nov 2007, Tony Duell wrote:
Over here, the term 'Heater Transformer' was
common, although 'Filament
The same in German (Heiztransformator); this makes two versus one ;-))
Talking about CRTs, I beleieve across the Pond, the
electodes are called
'cathode', 'grid 1', 'grid 2'.... 'anode'. Over here
they're 'cathode'
'grid'. 'anode 1' (or 'first anode'), 'anode 2'
('second anode')... (the
last one, the aquadaq coating inside the flare, connected to the EHT
supply, is called the 'final anode' most of the time).
Usually the grid is called Wehnelt cylinder because of its inventor and
its shape.
Christian
9 Nov
9 Nov
5 p.m.
Talking about
CRTs, I beleieve across the Pond, the electodes are called
'cathode', 'grid 1', 'grid 2'.... 'anode'. Over here
they're 'cathode'
'grid'. 'anode 1' (or 'first anode'), 'anode 2'
('second anode')... (the
last one, the aquadaq coating inside the flare, connected to the EHT
supply, is called the 'final anode' most of the time).
Usually the grid is called Wehnelt cylinder because of its inventor and
its shape. 
7 Nov
7 Nov
10:04 p.m.
On Nov 7, 2007, at 7:17 PM, Tony Duell wrote:
This may be a UK .vs. US language difference, but to me :
A 'filament' is a thin wire, heated electircally. A heater (in a
valve)
is a particular type of filament
A filament that's also the cathode (as here) is a 'directly heated
cathode'
A filament that heats a separate cathode is called a 'heater'. The
result
is caleld an 'indirectly heated cathode'
This is the way I learned it, and I'm in the US.
-Dave
--
Dave McGuire
Port Charlotte, FL
Farewell Ophelia, 9/22/1991 - 7/25/2007
[...] the two wires that are a filliment (heater to
some).
As I understand it, a filament and heater are not just two different
words for the same thing (for a long time I thought they were...).
A filament is what this is: the electron emitter is the same thing
that
is generating the heat through ohmic losses. A heater is a case
where
the heat generator is not the same thing that is emitting
electrons, as
in many vacuum tubes: the heater generates heat, which then warms up
the (separate) cathode electrode. 
10:11 p.m.
Dave McGuire wrote:
My own opinion on the subject has been colored by "Star Trek" and
"quantum filaments".
Peace... Sridhar
This may be a
UK .vs. US language difference, but to me :
A 'filament' is a thin wire, heated electircally. A heater (in a valve)
is a particular type of filament
A filament that's also the cathode (as here) is a 'directly heated
cathode'
A filament that heats a separate cathode is called a 'heater'. The result
is caleld an 'indirectly heated cathode'
This is the way I learned it, and I'm in the US.
11:34 p.m.
Sign. Terminology changes over time, particularly in technology.
When I was young, I learned about "condensers" and "aerials" from my
father. "Breadboarding" a circuit meant pretty much that--
constructing it on a plank of wood, preferably using #14 bare copper
wire laid out in neat right angles.
By the time I was a teenager, my speech habits had been corrected to
say "capacitor" and "antenna".
I like the distinction between "filament" and "heater". The latter
implies that something is being heated. The former implies a
standalone glowing wire. "Indirectly heated" and "directly heated"
may be a bit more accurate, but the terms are also cumbrous.
And whoever heard of "nanofarads" or "picofarads" anyway? ;)
Cheers,
Chuck
8 Nov
8 Nov
7:05 a.m.
From: cclist at sydex.com> > And whoever heard
of "nanofarads" or "picofarads" anyway? ;)> >
micro-microfarads is what I learned.
Dwight
_________________________________________________________________
Windows Live Hotmail and Microsoft Office Outlook ? together at last. ?Get it now.
http://office.microsoft.com/en-us/outlook/HA102225181033.aspx?pid=CL1006269…
7:30 a.m.
On Thu, 8 Nov 2007 07:05:21 -0800, dwight elvey wrote:
Uncle Sams Misguided Children, taught us Mickey-Mikes.
From: cclist
at sydex.com> > And whoever heard of "nanofarads" or
"picofarads" anyway? ;)> >
micro-microfarads is what I learned. From the minds of these same military educators came;
Bad Boys <Ravage> Our Young Girls But Violet Goes Willingly ..... Get Some
Now
0 Black, 1 Brown, 2 Red, 3 Orange, 4 Yellow, 5 Green, 6 Blue, 7 Violet, 8 Gray, 9 White,
5% Gold, 10% Silver, None
and the clasic ...
Sin = Oscar / Had
Cosin = A / Harry
Tangent = Old / Ass
Back under my rock :)
The other Bob
9:51 a.m.
Chuck Guzis wrote:
Sign. Terminology changes over time, particularly in
technology.
When I was young, I learned about "condensers" and "aerials" from my
father. "Breadboarding" a circuit meant pretty much that--
constructing it on a plank of wood, preferably using #14 bare copper
wire laid out in neat right angles.
By the time I was a teenager, my speech habits had been corrected to
say "capacitor" and "antenna".
I like the distinction between "filament" and "heater". The latter
implies that something is being heated. The former implies a
standalone glowing wire. "Indirectly heated" and "directly heated"
may be a bit more accurate, but the terms are also cumbrous.
And whoever heard of "nanofarads" or "picofarads" anyway? ;)
Throws in femto-farards (fF). f = 10^-16 Used in IC[1] design.
Cheers,
Chuck
You know the stuff that goes *boom* when you connect 300 volts
bettween Vcc and Ground.
11 a.m.
On Thursday 08 November 2007 02:34, Chuck Guzis wrote:
Sign. Terminology changes over time, particularly in
technology.
When I was young, I learned about "condensers" and "aerials" from my
father. "Breadboarding" a circuit meant pretty much that--
constructing it on a plank of wood, preferably using #14 bare copper
wire laid out in neat right angles.
By the time I was a teenager, my speech habits had been corrected to
say "capacitor" and "antenna".
I like the distinction between "filament" and "heater". The latter
implies that something is being heated. The former implies a
standalone glowing wire. "Indirectly heated" and "directly heated"
may be a bit more accurate, but the terms are also cumbrous.
And whoever heard of "nanofarads" or "picofarads" anyway? ;)
"MMFD"! Usually wax-coated cardboard. :-)
Reminds me of a question that got thrown at me during a recent job interview.
The guy threw three colors at me and asked me what value resistor that
represented, which was fairly trivial to answer. Then he asked me what
tolerance it was. I responded that he didn't mention a tolerance band, at
which point he told me that there wasn't one.
"20%, though I haven't run into one of those in quite a while..."
:-)
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
11:18 a.m.
Reminds me of a question that got thrown at me during
a recent job
interview. The guy threw three colors at me and asked me what value
resistor that represented, [...]
http://xkcd.com/227/
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1:33 p.m.
Reminds me of a question that got thrown at me during
a recent job interv=
iew. =20
The guy threw three colors at me and asked me what value resistor that=20
represented, which was fairly trivial to answer. Then he asked me what=20
tolerance it was. I responded that he didn't mention a tolerance band, =
at=20
which point he told me that there wasn't one.
"20%, though I haven't run into one of those in quite a while..."
Did he pack a set of colours that could have been a prefered value in the
20% series? I would have been worried if he'd said something like
'Orange, White, Red', since AFAIK 3.9k resistors never made with a 20%
tolerance...
-tony
9 Nov
9 Nov
10:41 p.m.
On Thursday 08 November 2007 16:33, Tony Duell wrote:
The colors he said were "green, black red". Dunno if you'd call that a
preferred value, but I've seen such.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
Reminds me of
a question that got thrown at me during a recent job
interview.
The guy threw three colors at me and asked me what value resistor that=20
represented, which was fairly trivial to answer. Then he asked me
what tolerance it was. I responded that he didn't mention a tolerance
band, at which point he told me that there wasn't one.
"20%, though I haven't run into one of those in quite a while..."
Did he pack a set of colours that could have been a prefered value in the
20% series? I would have been worried if he'd said something like
'Orange, White, Red', since AFAIK 3.9k resistors never made with a 20%
tolerance...
10 Nov
10 Nov
1:46 p.m.
The colors he said were "green, black red".
Dunno if you'd call that a=20
preferred value, but I've seen such.
OK, so 5k obviously... Not a common value in any series these days
I think my question would then have been : Are you sure it was a resistor?
I've seen picofuses with those colours (5000mA = 5A), although IIRC, they
normally have a 4th band giving the time-delay charactistics.
-tony
3:25 p.m.
On Saturday 10 November 2007 16:46, Tony Duell wrote:
No, not these days, but back when 20% tolerance parts were common you'd run
into stuff like that from time to time. Lots of those old wax-coated paper
caps were ".05 MFD" rather than the 0.047uF that you run into these days (or
47nF, for that matter).
The colors he
said were "green, black red". Dunno if you'd call that
a=20 preferred value, but I've seen such.
OK, so 5k obviously... Not a common value in any series these days I think my question would then have been : Are you
sure it was a resistor?
I've seen picofuses with those colours (5000mA = 5A), although IIRC, they
normally have a 4th band giving the time-delay charactistics.
I didn't have time for questions, at least none coming from my end -- there
were four folks rapidly shooting them at me, in all sorts of different
areas. Overall I think it went well, and I just wish they'd hurry up and
let me know where I stand with this.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
4 p.m.
On 10 Nov 2007 at 18:25, Roy J. Tellason wrote:
No, not these days, but back when 20% tolerance
parts were common you'd run
into stuff like that from time to time. Lots of those old wax-coated paper
caps were ".05 MFD" rather than the 0.047uF that you run into these days (or
47nF, for that matter).
One should have quizzed the interviewer on the old-style carbon
resistors--body, end, dot coding...
Cheers,
Chuck
4:14 p.m.
On Saturday 10 November 2007 19:00, Chuck Guzis wrote:
On 10 Nov 2007 at 18:25, Roy J. Tellason wrote:
Heh. I do know about those, though it's been a *really* long time since I've
encountered one. I don't know that this guy would've known what I was
talking about, though, he was younger than I am...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
No, not these days, but back when 20% tolerance
parts were common you'd
run into stuff like that from time to time. Lots of those old wax-coated
paper caps were ".05 MFD" rather than the 0.047uF that you run into these
days (or 47nF, for that matter).
One should have quizzed the interviewer on the old-style carbon
resistors--body, end, dot coding...
4:34 p.m.
On 10 Nov 2007 at 19:14, Roy J. Tellason wrote:
Heh. I do know about those, though it's been a
*really* long time since I've
encountered one. I don't know that this guy would've known what I was
talking about, though, he was younger than I am...
When I was *much* younger, I used to run into them occasionally.
The BED coding made no practical sense to me. DEB would have made
more sense, allowing one to recognize the multiplier with a glance,
instead of grabbing the resistor and maniuplating it to see if what
you have is a 470 or 47K ohm reisstor. When these things were
soldered tightly to mounting strips in military equipment, it could
get to be downright frustrating.
Another one to confuse-a-boss would be 6-dot mica capacitor color
code (one could find these on 1960's computer equipment). I probably
still have a few of these in operation.
Cheers,
Chuck
4:36 p.m.
On Saturday 10 November 2007 19:34, Chuck Guzis wrote:
Another one to confuse-a-boss would be 6-dot mica
capacitor color
code (one could find these on 1960's computer equipment). I probably
still have a few of these in operation.
Yes, and those still confuse me, too, sometimes...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
5:56 p.m.
When I was *much* younger, I used to run into them
occasionally.
The BED coding made no practical sense to me. DEB would have made
more sense, allowing one to recognize the multiplier with a glance,
instead of grabbing the resistor and maniuplating it to see if what
you have is a 470 or 47K ohm reisstor. When these things were
soldered tightly to mounting strips in military equipment, it could
get to be downright frustrating.
It should be noted that BED resistors were almost never used by the US
military. The exception was during a few years in the 1930s, and only
in a few pieces of equipment. By 1940, the US military had gone
completely with the stripe system.
Another one to confuse-a-boss would be 6-dot mica
capacitor color
code (one could find these on 1960's computer equipment). I probably
still have a few of these in operation.
It should also be noted that there never was a universally adopted
color code scheme for capacitors. The RMA tried for many years to get
the manufacturers to adhere to the standards, but were very
unsuccessful. The best scheme when dealing with these is to look for
the two dots that make sense as the value, and see if the next, often
around the corner, is a valid multiplier color.
While not a common occurence, I have seen the color coded "postage
stamp" caps on IBM SMS cards from the 1960 era.
--
Will
6:26 p.m.
On 10 Nov 2007 at 20:56, William Donzelli wrote:
It should be noted that BED resistors were almost
never used by the US
military. The exception was during a few years in the 1930s, and only
in a few pieces of equipment. By 1940, the US military had gone
completely with the stripe system.
It's entirely possible that I recall a piece of commercial gear, not
military. But they were frustrating to read when soldered in.
unsuccessful. The best scheme when dealing with these
is to look for
the two dots that make sense as the value, and see if the next, often
around the corner, is a valid multiplier color.
I'll still take those over caps whose value is given by little glued-
on bits of paper. I've got some GTE gear that's built like that.
Curiously, the postage-stamp (Sangamo) micas don't have the color
dots filled in, but rather have the value printed on the reverse
side.
While not a common occurence, I have seen the color
coded "postage
stamp" caps on IBM SMS cards from the 1960 era.
I've got a couple on some MPI floppy drives were I needed to adjust
the LP filtering on. I had some mica caps scavenged from some 60's
vacuum-tube computer gear that I pressed into use. They're still in
the circuit and working just fine.
Cheers,
Chuck
6:06 p.m.
No, not these days, but back when 20% tolerance
parts were common you'd run
into stuff like that from time to time.
5.0 was a standard value in an earlier system, in the early 1930s.
Three other things to consider with your quiz resistor:
Was the first band twice as thick as the others? If so, it was
wirewound, and can be thought of as being one standard size bigger for
power dissipation.
Was the body color a light tan, rather than standard brown? If so, it
was insulated. This part of the standard died quickly, as the method
of making resistors out of solid chunks of carbon with no insulation
on the outer skin went away.
And very unlikely with a 20 percent resistor (no tolerance band), was
there one more band, in the fifth position? This was used for some
time by the military to signify all sorts of things, like reliability,
stability, and so forth. Univac fell in love with the fifth band.
--
Will
8 Nov
8 Nov
12:53 p.m.
Sign. Terminology changes over time, particularly in technology.
When I was young, I learned about "condensers" and "aerials" from my
father. "Breadboarding" a circuit meant pretty much that--
constructing it on a plank of wood, preferably using #14 bare copper
wire laid out in neat right angles.
By the time I was a teenager, my speech habits had been corrected to
say "capacitor" and "antenna".
'Aerial' is still the common term over here ('antenna' is understood, but
sounds wrong). But the only time you'll see the word 'condenser' used is
in old books and in one old radio magazine that insistes on using the old
terms (including 'cylces per second' for 'hertz').
I like the distinction between "filament" and "heater". The latter
implies that something is being heated. The former implies a
standalone glowing wire. "Indirectly heated" and "directly heated"
may be a bit more accurate, but the terms are also cumbrous.
They actually refer to subtly differnt things. 'Directly heated' and
'Indirectly heated' refer to the actual cathode -- the thing that emits
electrons. 'Filament' and 'Heater' refer to the use made of the glowing
thin wire. OK, a 'directly heated cathode' and a 'filament' are much the
same thing (as in the indicator tube that started this thread), but
'heater' and 'indirectly heated cathode' are different things.
And whoever heard of "nanofarads" or "picofarads" anyway? ;)
I'm old enough to remember 'micro-micro-farads' :-)
-tony
3:26 p.m.
On Thu, 8 Nov 2007, Tony Duell wrote:
sounds wrong). But the only time you'll see the
word 'condenser' used is
in old books and in one old radio magazine that insistes on using the old
terms (including 'cylces per second' for 'hertz').
It is still in common usage to refer to the capacitor used in automotive
distributors
Sorry, Jay
3:45 p.m.
On Nov 8, 2007, at 6:26 PM, Fred Cisin wrote:
That's because the automotive industry is clueless. ;)
-Dave
--
Dave McGuire
Port Charlotte, FL
sounds wrong).
But the only time you'll see the word 'condenser' used
is
in old books and in one old radio magazine that insistes on using the
old
terms (including 'cylces per second' for 'hertz').
It is still in common usage to refer to the capacitor used in
automotive
distributors
9 Nov
9 Nov
5:04 p.m.
On Thu, 8 Nov 2007, Tony Duell wrote:
Yes, but how common are LT contact breakers these days? Heck, most modenr
cars over here have a coil-per-plug (or at least a coil for every pair of
plugs, with a 'weated spark' occuring at a plug in a cylinder at the top
of the exhaust stroke), so no distributor at all.
That said, the workshop manaul I've just picked up (for a 1972 Rover P6)
refers to the component as the capacitor.
-tony
sounds wrong). But the only time you'll see
the word 'condenser' used is
in old books and in one old radio magazine that insistes on using the old
terms (including 'cylces per second' for 'hertz').
It is still in common usage to refer to the capacitor used in automotive
distributors
10 Nov
10 Nov
4:43 a.m.
On Nov 9, 2007, at 8:04 PM, Tony Duell wrote:
Yes, but how common are LT contact breakers these days? Heck, most
modenr
cars over here have a coil-per-plug (or at least a coil for every pair
of
plugs, with a 'weated spark' occuring at a plug in a cylinder at the
top
of the exhaust stroke), so no distributor at all.
Indeed, my last car had TWO coils per plug and no distributor.
Buying a set of spark plug wires for that thing was...painful.
-Dave
--
Dave McGuire
Port Charlotte, FL
sounds wrong). But the only time you'll see the
word 'condenser'
used is
in old books and in one old radio magazine that insistes on using
the old
terms (including 'cylces per second' for 'hertz').
It is still in common usage to refer to the capacitor used in
automotive
distributors
8 Nov
8 Nov
12:49 p.m.
Dave McGuire wrote:
I'd love to see you keep that flame burning while having a sufficienltly
low gas pressure around the cathode to have a long enough mean free path
for the electrons, Not to mention problems caused by the ions geenrated
by said flame.
-tony
This is the way I learned it, and I'm in
the US.
Forget electrcity ... Have a torch heated valve. :)
11:28 p.m.
Forget
electrcity ... Have a torch heated valve. :)
I'd love to see you keep that
flame burning while having a
sufficienltly low gas pressure around the cathode to have a long
enough mean free path for the electrons, Not to mention problems
caused by the ions geenrated by said flame.
9 Nov
9 Nov
12:17 a.m.
On 9 Nov 2007 at 2:28, der Mouse wrote:
The glass envelope for the vacuum takes the form of
two concentric
cylinders joined at their ends, topologically a torus. The cathode is
another concentric cylinder, this time of metal or whatever, just
barely larger than the inner glass cylinder, with the grids and
anode/plate forming successively larger cylinders. The heater flame
passes through the centre of the cylinder (which is outside the glass
vacuum envelope), heating the cathode by infrared radiation, much as a
conventional heater does. (The glass forming the inner cylinder needs
to be infrared-transparent and probably high-melting-point.)
Interesting idea, but why not a simple copper cathode extending
through the (silica) envenlope and heated externally? Thermal
conduction should give you enough for thermionic emission on the
interior. I wonder if it's already been done--as a high-temperature
measuring device.
On the subject of cathodes (and vintage computers), whatever happened
to the tunnel cathode? Back in the 60's, there was a lot of work
(some by IBM) going on with CRTs utilitizing them and there were
predictions that tunnel-cathode tubes in general would make electron
tubes as reliable as the transistor.
Cheers,
Chuck
10:59 p.m.
On Friday 09 November 2007 02:28, der Mouse wrote:
Doable.
The glass envelope for the vacuum takes the form of two concentric
cylinders joined at their ends, topologically a torus. The cathode is
another concentric cylinder, this time of metal or whatever, just
barely larger than the inner glass cylinder, with the grids and
anode/plate forming successively larger cylinders. The heater flame
passes through the centre of the cylinder (which is outside the glass
vacuum envelope), heating the cathode by infrared radiation, much as a
conventional heater does. (The glass forming the inner cylinder needs
to be infrared-transparent and probably high-melting-point.)
This is pretty much the way I pictured it, too...
Working out the details would be a real killer, though.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
Forget electrcity ... Have a torch heated valve. :)
I'd love to see you keep that flame burning while having a
sufficienltly low gas pressure around the cathode to have a long
enough mean free path for the electrons, Not to mention problems
caused by the ions geenrated by said flame. 
2:25 a.m.
On Thursday 08 November 2007 20:49:34 Tony Duell wrote:
Bring a copper bar out through the envelope to heat the cathode, like old
hot-tube ignition systems.
Gordon
Dave McGuire
wrote:
I'd love to see you keep that flame burning while having a sufficienltly
low gas pressure around the cathode to have a long enough mean free path
for the electrons, Not to mention problems caused by the ions geenrated
by said flame. This is the way I learned it, and I'm in
the US.
Forget electrcity ... Have a torch heated valve. :)
8 Nov
8 Nov
1:45 a.m.
On Thu, 8 Nov 2007, Tony Duell wrote:
This may be a UK .vs. US language difference, but to
me :
A 'filament' is a thin wire, heated electircally. A heater (in a valve)
is a particular type of filament
A filament that's also the cathode (as here) is a 'directly heated cathode'
A filament that heats a separate cathode is called a 'heater'. The result
is caleld an 'indirectly heated cathode'
Exactly; it's the same in German: "Heizfaden" (heater/filament),
"direkt
geheizte Katode" (directly heated cathode) and "indirekt geheizte Katode"
(indirectly heated cathode).
Christian
10:47 a.m.
On Wednesday 07 November 2007 19:17, Tony Duell wrote:
This may be a UK .vs. US language difference, but to me :
A 'filament' is a thin wire, heated electircally. A heater (in a valve)
is a particular type of filament
A filament that's also the cathode (as here) is a 'directly heated cathode'
A filament that heats a separate cathode is called a 'heater'. The result
is caleld an 'indirectly heated cathode'
-tony
That's always been the way I understood it as well, so I don't think we're
dealing with any across-the-pond language differences here...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
[...] the two wires that are a filliment (heater to
some).
As I understand it, a filament and heater are not just two different
words for the same thing (for a long time I thought they were...).
A filament is what this is: the electron emitter is the same thing that
is generating the heat through ohmic losses. A heater is a case where
the heat generator is not the same thing that is emitting electrons, as
in many vacuum tubes: the heater generates heat, which then warms up
the (separate) cathode electrode.
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ajp166＠bellatlantic.net -
ard＠p850ug1.demon.co.uk -
bfranchuk＠jetnet.ab.ca -
caveguy＠sbcglobal.net -
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cclist＠sydex.com -
cisin＠xenosoft.com -
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mouse＠Rodents.Montreal.QC.CA -
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rtellason＠verizon.net -
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