Triode - Tetrode - Pentode - (What comes next)

[experimenter@nowhere.com]

Vacuum tubes were always identified by the number of electrodes inside
the tube. There were
Diode (2) Triode (3) Tetrode (4) and Pentode (5)

There was also a Hexode which was a tube with TWO triodes inside.
I've seen reference to an Octode, but cant find a definition.

My question is this: Did they ever make tubes with more than five
electrodes (not including the dual varieties meaning more than one
"tube" inside the same envelope)

If they did make tubes with 6 or 7 or 8 or more electrodes, what were
they called?

* Yea, I still like playing around with tubes *

Thanks

 

[Phil Allison]

Vacuum tubes were always identified by the number of electrodes inside
the tube. There were
Diode (2) Triode (3) Tetrode (4) and Pentode (5)

There was also a Hexode which was a tube with TWO triodes inside.

** Nope - that particular combo is called a "twin triode".

I've seen reference to an Octode, but cant find a definition.

** That is a tube with eight tentacles.

My question is this: Did they ever make tubes with more than five
electrodes (not including the dual varieties meaning more than one
"tube" inside the same envelope)

** Eeeeeeyep.

If they did make tubes with 6 or 7 or 8 or more electrodes, what were
they called?

** Look up "pentagrid converter".

Has 7 electrodes.

* Yea, I still like playing around with tubes *

** Would never have guessed........



.... Phil

 

[Sjouke Burry]

Vacuum tubes were always identified by the number of electrodes inside
the tube. There were
Diode (2) Triode (3) Tetrode (4) and Pentode (5)

There was also a Hexode which was a tube with TWO triodes inside.
I've seen reference to an Octode, but cant find a definition.

My question is this: Did they ever make tubes with more than five
electrodes (not including the dual varieties meaning more than one
"tube" inside the same envelope)

If they did make tubes with 6 or 7 or 8 or more electrodes, what were
they called?

* Yea, I still like playing around with tubes *

Thanks

Photo multiplier tube, contains a cascade of "anodes".

Also some special oscillator/mixer tubes, Octode just
means 8 electrodes tube.

 

[tm]

Vacuum tubes were always identified by the number of electrodes inside
the tube. There were
Diode (2) Triode (3) Tetrode (4) and Pentode (5)

There was also a Hexode which was a tube with TWO triodes inside.
I've seen reference to an Octode, but cant find a definition.

My question is this: Did they ever make tubes with more than five
electrodes (not including the dual varieties meaning more than one
"tube" inside the same envelope)

If they did make tubes with 6 or 7 or 8 or more electrodes, what were
they called?

* Yea, I still like playing around with tubes *

Thanks

How about nixie tubes?

 

[upsidedown@downunder.com]

My question is this: Did they ever make tubes with more than five
electrodes (not including the dual varieties meaning more than one
"tube" inside the same envelope)

If they did make tubes with 6 or 7 or 8 or more electrodes, what were
they called?

Enneodes (7 grids+anode+cathode) such as EQ80 were mainly used as FM
detectors.

Heptodes, hexodes,octodes and other tubes with a lot of grids were
often used as multipliers, the first control grid reduced the original
electron flow from the cathode and the second control grid modulated
the remaining electron flow, thus producing the product of the control
signals (each having a multiplication factor 0..1).

The additional screen and suppressor grids are needed to keep the
control grids separated (independent) and removing the electrons that
are not intended to flow to the second control grid or anode.

 

[Jamie]

Vacuum tubes were always identified by the number of electrodes inside
the tube. There were
Diode (2) Triode (3) Tetrode (4) and Pentode (5)

There was also a Hexode which was a tube with TWO triodes inside.
I've seen reference to an Octode, but cant find a definition.

My question is this: Did they ever make tubes with more than five
electrodes (not including the dual varieties meaning more than one
"tube" inside the same envelope)

If they did make tubes with 6 or 7 or 8 or more electrodes, what were
they called?

* Yea, I still like playing around with tubes *

Thanks

I don't know if it counts but I have 2, 12 element photo multiplier
tubes sitting around my place worth some money..

Jamie

 

[Jan Panteltje]

There were also octodes & nonodes.

AFAIK it never caught on though.

It was a no-no de.

 

[upsidedown@downunder.com]

Now you mention it, heptodes and hexodes were in existance, but the
dim memory, rescued by your mentioning, indicated they were rare /
rarely used (and not for long).

At least in Europe ECHnn and UCHnn triode heptodes were common, the
triode was the local oscillator and the heptode was the mixer.

Due to the very high background band noise on LF, MF and lower part of
the HF band, the high heptode noise was not an issue, when even a semi
decent outdoor antenna was used.

On the upper part of the HF band and in the VHF band (FM), the band
noise is low and the heptode noise would be unacceptable without one
or two triode RF stages before the mixer, making a heptode mixer less
attractive alternative.

 

[Tim Williams]

And electrostatic deflection CRTs.

ftp://jjlarkin.lmi.net/547_crt.JPG

Mine's fancier:

http://myweb.msoe.edu/williamstm/Images/Tek475_5.jpg

Spiral wound deflection plates, with ground planes on either side, and the
pitch and width of the spiral varies along the path of the beam. I can't
imagine how much pain they went through to get that right.

Tim